Below I am adding more lists from where you can try to build backlinks for high authority sites for absolutely free of cost.
S.No Dofollow Profile Creation Websites
1 goodreads.com
2 gopro.com
3 grabcad.com
4 gust.com
5 habricentral.org
6 hackathon.io
7 hackerrank.com
8 hairtrade.com.au
9 hashatit.com
10 hearthis.at
11 hireclub.com
12 holonis.com
13 hoverboard.io
14 hub.docker.com
15 hubpages.com
16 hubski.com
17 hungrygowhere.com
18 huntingnet.com
19 huzzaz.com
20 ibegin.com
21 id.arduino.cc
22 id.docker.com
23 idm.xfinity.com
24 ihubbub.com
25 imclassified.com
26 imcreator.com
27 in.pinterest.com
28 independent.academia.edu
29 indiblogger.in
30 infd.in
31 infobarrel.com
32 infragistics.com
33 inmobi.com
34 instapaper.com
35 instructables.com
36 intensedebate.com
37 interweave.com
38 islumped.com
39 issuu.com
40 italymagazine.com
41 itsmyurls.com
42 jodohkita.info
43 jofrati.net
44 jovoto.com
45 kbforum.dragondoor.com
46 kickstarter.com
47 kinzaa.com
48 kiva.org
49 knowem.com
50 knowyourmeme.com
51 kongregate.com
52 ksl.com
53 laracasts.com
54 last.fm
55 lawlink.com
56 lingr.com
57 linustechtips.com
58 list.ly
59 listitsellit.us
60 listography.com
61 livejournal.com
62 lms.biotecnika.org
63 locanto.net
64 lockerdome.com
65 login.aol.com
66 logopond.com
67 london8.net
68 lookbook.nu
69 loop.frontiersin.org
70 lymelightwebs.net
71 machsupport.com
72 madewithvuejs.com
73 magnitt.com
74 maprecord.com
75 maqtoob.com
76 mastermind.bizsugar.com
77 medium.com
78 meetup.com
79 melbournebd.com.au
80 members.adlandpro.com
81 dupioneer.com
82 dzone.com
83 edocr.com
84 eeweb.com
85 ello.co
86 enetget.com
87 equitynet.com
88 etchcraftemporium.brandyourself.com
89 etsy.com
90 evernote.com
91 fanpop.com
92 fearsteve.com
93 feedsfloor.com
94 filmsforaction.org
95 financial-hub.net
96 findnerd.com
97 flattr.com
98 flipboard.com
99 follr.com
100 follr.me
101 forum.abantecart.com
102 forum.cs-cart.com
103 forum.excellent-supply.com
104 forum.melanomainternational.org
105 forum.mikrotik.com
106 forum.peppermintos.com
107 forum.zentyal.org
108 forums.envato.com
109 forums.sentora.org
110 forums.spry.com
111 forums.wandboard.org
112 freelistingindia.in
113 funadvice.com
114 funderhut.com
115 gamedev.net
116 gameinformer.com
117 gapyear.com
118 giphy.com
119 github.com
120 gitlab.com
121 codecademy.com
122 codeproject.com
123 colourlovers.com
124 comfortinstitute.org
125 community.justlanded.com
126 community.today.com
127 completed.com
128 coolors.co
129 cosap.org
130 coursera.orgaccount-profile
131 crej.com
132 crooksandliars.com
133 crunchbase.com
134 crunchyroll.com
135 csslight.com
136 culturadigital.br
137 czechtribe.com
138 dailygram.com
139 dandad.org
140 darkreading.com
141 dedaluspress.com
142 dentons.net
143 desall.com
144 desidime.com
145 designspiration.netsettings
146 devdojo.com
147 developers.refinitiv.com
148 deviantart.com
149 diggerslist.com
150 discogs.com
151 disqus.com
152 dpreview.com
153 dreamwidth.org
154 dreevoo.com
155 dribbble.com
156 droidxforums.com
157 drupal.org
158 duck.co
159 duck.couser365pestcontrol
160 du-in.academia.eduAlpineInfosoft
161 archive.org
162 arduino.cc
163 artfire.com
164 artmight.com
165 artstation.com
166 asklaila.com
167 askmehelpdesk.com
168 auth.arduino.cc
169 authorstream.com
170 bagtheweb.com
171 bandcamp.com
172 bbs.phoenixstudio.org
173 bcmoney-mobiletv.com
174 behance.net
175 benchrest.com
176 bibliocrunch.com
177 bibsonomy.org
178 bitrated.com
179 bloglovin.com
180 blogtalkradio.com
181 bookmarkingbase.com
182 bookmarktou.com
183 boredpanda.com
184 brandyourself.com
185 brooklynne.net
186 business.com
187 buzzfeed.com
188 buzzsprout.com
189 cafebabel.com
190 caithness-business.co.uk
191 calendly.com
192 canadavisa.com
193 cbseguess.com
194 change.org
195 cheaperseeker.com
196 chirbit.com
197 cityslick.net
198 classifiedscachevalley.com
199 clickindia.com
200 clipix.com
201 bookmax.net
202 1look4.com
203 23hq.com
204 3000bonus.com
205 30boxes.com
206 365pestcontrol.dreamwidth.org
207 3dprintboard.com
208 40billion.com
209 4networking.biz
210 4shared.com
211 500px.com
212 8tracks.com
213 about.me
214 aboutus.com
215 accounts.craigslist.org
216 activei.forumcrea.com
217 adclassified.in
218 addons.mozilla.org
219 addthismark.com
220 addwish.com
221 adfreeposting.com
222 adsansar.com
223 adsoftheworld.com
224 aeon.co
225 affiliated-business.com
226 aihitdata.com
227 aileensoul.com
228 aitoc.com
229 akonter.com
230 alcoholink.community
231 alltrails.com
232 alpineinfosoft.netboard.me
233 als.anits.edu.in
234 alumni.lpu.in
235 amazon.com
236 angel.co
237 anotepad.com
238 app.bitly.com
239 appfutura.com
240 archilovers.com
241 http://www.smartguy.com
242 http://www.plerb.com
243 http://www.managewp.org
244 http://www.ourpatch.com.au
245 http://www.forums.spry.com
246 http://www.sportclubplatz.com/jforum
247 http://www.fearsteve.com
248 http://www.brijj.com
249 http://www.freeadstime.org
250 http://www.twatter.com
251 http://www.slideonline.com
252 http://www.nfomedia.com
253 http://www.completed.com
254 http://www.bitrix24.net
255 http://www.p-tweets.com
256 http://www.loopdesk.com
257 http://www.zoomgroups.net
258 http://www.listango.com
259 http://www.mehfeel.net/mehfeel
260 http://www.articlesbd.com
261 http://www.painterfactory.com
262 http://www.cloudytags.com
263 http://www.bitsdaq.com
264 http://www.cinenetworld.com
265 http://www.mootin.com
266 http://www.app.g2link.com
267 http://www.blackdtools.com
268 http://www.linkorado.com
269 http://www.pitnit.com
270 http://www.kippee.com
271 http://www.topishare.com
272 http://www.banggood.in
273 http://www.mioola.com
274 http://www.tcnext.com
275 http://www.forums.otterhub.org
276 http://www.fails.us
277 http://www.serenacentral.com
278 http://www.master-land.net
279 http://www.valutasitoweb.com
280 http://www.fionadates.com
281 http://www.gostartups.in
282 http://www.queenofdating.net
283 http://www.alternion.com
284 http://www.lookuppage.com
285 http://www.referralkey.com
286 http://www.imgfave.com
287 http://www.wadja.com
288 http://www.forums.formz.com
289 http://www.websitebuilder.com
290 http://www.webestools.com
291 http://www.pixelation.org
292 http://www.ispionage.com
293 http://www.pentaxuser.com
294 http://www.telugupeople.com
295 http://www.muamat.com
296 http://www.nationaldb.org
297 http://www.siftery.com
298 http://www.huntingnet.com/forum
299 http://www.xbiz.net
300 http://www.blurpalicious.com
301 http://www.anotepad.com
302 http://www.tuugo.us
303 http://www.lingr.com
304 http://www.chemicalforums.com
305 http://www.maxforlive.com
306 http://www.softcity.com
307 http://www.jigsy.com
308 http://www.rehashclothes.com
309 http://www.brooklynne.net
310 http://www.forum.alwaysdata.com
311 http://www.forum.kvinneguiden.no
312 http://www.koombea.com
313 http://www.trepup.com
314 http://www.lawschooldiscussion.org
315 http://www.houzz.in
316 http://www.arto.com
317 http://www.bookmax.net
318 http://www.zumvu.com
319 http://www.follr.com
320 http://www.tupalo.co
321 http://www.addwish.com
322 http://www.ironsightgame.com
323 http://www.listography.com
324 http://www.elocal.com
325 http://www.23hq.com
326 http://www.prsync.com
327 http://www.redgage.com
328 http://www.aprelium.com/forum
329 http://www.chatroll.com
330 http://www.forum.unilang.org
331 http://www.chordie.com
332 http://www.chordie.com/forum/index.php
333 http://www.convo.com
334 http://www.meraevents.com
335 http://www.theloop.com.au
336 http://www.forum.pj64-emu.com
337 http://www.ttlink.com
338 http://www.artician.net
339 http://www.schoolofeverything.com
340 http://www.skyrock.com
341 http://www.sitebuilder.com
342 http://www.vbprofiles.com
343 http://www.visajourney.com/forums
344 http://www.erfworld.com
345 http://www.twitxr.com
346 http://www.jazz.net
347 http://www.bagtheweb.com
348 http://www.espguitars.com
349 http://www.yakaz.com
350 http://www.lambda-the-ultimate.org
351 http://www.funadvice.com
352 http://www.try.tibbr.com
353 http://www.icyte.com
354 http://www.site123.com
355 http://www.storeboard.com
356 http://www.webstarts.com
357 http://www.appearoo.com
358 http://www.sett.com
359 http://www.lawlink.com
360 http://www.chirbit.com
361 http://www.citysquares.com
362 http://www.clickindia.com
363 http://www.askmehelpdesk.com
364 http://www.inmethod.com
365 http://www.delphiforums.com
366 http://www.myvidster.com
367 http://www.community.endnote.com
368 http://www.dropshots.com
369 http://www.knowem.com
370 http://www.mootools.net
371 http://www.scout.org
372 http://www.feedspot.com
373 http://www.local.com
374 http://www.smartdatacollective.com
375 http://www.yourlisten.com
376 http://www.bigsoccer.com
377 http://www.folkd.com
378 http://www.chirb.it
379 http://www.pregame.com
380 http://www.filmsforaction.org
381 http://www.lightstalking.com
382 http://www.authorsden.com
383 http://www.spoke.com
384 http://www.bark.com
385 http://www.bark.com/en/gb
386 http://www.screenskills.com
387 http://www.slideserve.com
388 http://www.communitywalk.com
389 http://www.30boxes.com
390 http://www.artwanted.com
391 http://www.hr.com
392 http://www.letstalkbitcoin.com
393 http://www.sitepronews.com
394 http://www.socialtext.com
395 http://www.writerscafe.org
396 http://www.photopeach.com
397 http://www.share.bizsugar.com
398 http://www.steepster.com
399 http://www.powershow.com
400 http://www.photodune.net
401 http://www.recruitingblogs.com
402 http://www.bluemaumau.org
403 http://www.forums.cat.com
404 http://www.graphicriver.net
405 http://www.propellerheads.com
406 http://www.dead.net
407 http://www.audiojungle.net
408 http://www.easel.ly
409 http://www.rhizome.org
410 http://www.symbaloo.com
411 http://www.thetoptens.com
412 http://www.gust.com
413 http://www.onmogul.com
414 http://www.answerbag.com
415 http://www.moc-pages.com
416 http://www.grabcad.com
417 http://www.muckrack.com
418 http://www.orcid.org
419 http://www.interweave.com
420 http://www.anobii.com
421 http://www.brandyourself.com
422 http://www.designrush.com
423 http://www.mightycause.