RBC Visa Infinite Avion sign up offer: 25,000 bonus points and first year free!
Points can be transferred to other frequent flyer programs and they sometimes have promos for extra points (like to British Airways Avios and Westjet)
This is the best signup bonus I've seen in a while. It's usually 15,000 points with no annual fee waiver.
Edit 1: Updated link in thread which does not contain a referral. http://www.rbcroyalbank.com/credit-card ... ASC=3C6002 (no fyf and 15k points only, refer to edit #6)
Edit 2: For existing RBC credit card holders, some people reported that they may only be receiving 15K bonus and potentially no FYF. The general consensus is to apply as if you were a new customer, which should get you 25K Avion points and FYF (don't enter your account details when applying to the card). Data Points are varied so YMMV on this.
Edit #3: Check post #394 by user djino who was successful in getting the 25k points and FYF despite being an existing RBC client. Thanks for sharing djino.
Edit #4: According to Rewards Canada (removed), April 30th 2018 was the last day although the link still seems to work. If you plan on applying, make sure to keep screenshots in case you get charged and/or you don't get 25K.
Edit #5: Reward Canada is now reporting that the new expiry date has been extended to May 31, 2018 (removed).
Edit #6: New and updated link: https://apps.royalbank.com/uaw0/iao/app ... main/intro (Thanks @X360 !)