Another stealth lover, excellent! So many good options already mentioned though.
Styx is under-exposed for how good it can be for pure stealthing with an old school feel to it. The jumping is far too forgiving/accurate, i always expect to fail the thin beam leaping areas but never have as of yet. Maybe due to the lack of animation for one-foot-off landings, I don't know. Chalk it up as a positive, either way.
I would say Abe's odyssee is quite stealth focused, lots of sneaking, insta-death, strategic thinking. They still mix it up with many other sections however.
Mark of the Ninja has been thoroughly recommended, so here is another + recommendation for it...can't hurt, right?
I'd imagine you might have played Far cry 3 and/or 4. In case you haven't though, the main crunchy centre of gameplay is wandering at your own pace, finding bases to stealthily take down. They can have some unscripted events which add to great moments of aggressive wildlife doing your job for you. With cathartic Elephant riding and hoverboat sliding for those why-the-fck-not momemts too!
Not sure what stealth inc. is like, have yet to be enticed enough to try.
I see the last of us here also, some pretty good stealth in that game. But it can and does often descend into anarchy. Perhaps there is a realistic option I have missed in there though. Oh, it has probably the best stealth based team-multiplayer I have experienced. Very tense. You learn many tactics as you play but they are very reluctant to give you silenced weapons at first. A quick wiki skim is advised beforehand, during and after.