The best replacement for sponsor is mentor.

The best alternatives to sponsor are rated as following:
★★★★★  mentor
★★★★  godparent
★★★  donation
★★★  sponsor
★★  partner
★★  sponser
★★  endorse
★★  donor
★  supporter
★  stakeholder
★  champion
★  investor
★  enroller doterra
★  underwriter
★  affiliate
★  plan administrator
★  owner
  project champion
  donate
  cosponsor
  change implementer
  project manager
  co sponsor
  borrower
  publisher
  petitioner
  patron
  title sponsor
  presenting sponsor
  household member

Your alternative for sponsor is not listed? Suggest!
Speaking about sponsor, one probably shouldn't forget about green card.

Other search terms related to sponsor and their ratings are:
★★★★★ green card
★★ scentsy
★ h1b
You have in mind a companion for sponsor and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of sponsor in all years. Click on graph for more.
sponsor
mentor
godparent