This app was mentioned in 3 comments, with an average of 5.33 upvotes
My word game, Hex-a-Word, is completely free, has no ads, and no IAPs.
https://play.google.com/store/apps/details?id=nz.personal.hexawordgame
My game: Hex-a-Word. I play it on long flights all the time.
https://play.google.com/store/apps/details?id=nz.personal.hexawordgame