(Available) Mon you'd be most excited to encounter in the wild?

I think a Tyranitar.

That said I would like to complete my regional dex by landing an Unown too.

Snorkax , never saw on radar sine I played from start

Kangaskhan, Heracross, Mr. Mine, Taurus in this order. I have no access to these regionals

Blissey 100% IV.

Unown, already have all others except regionals or could evolve them by walking for candy

Lapras - I only ever saw once, in a gym
Mareep/Flaaffy/Ampharos - only once I saw the shadow of Mareep but had to stay on route.

The events took care of most of my other wishes (I'd like higher IV or level for some I am ready to evolve)

Girafarig! Only mon I'm missing excluding regionals and unown.

Unown. The rest, except for regionals can be obtained thru walking and egg hatches.

Since I was lucky enough to catch 4 (!) Dragonites in the wild already, I would get an heart attack if I came across a wild Tyranitar. Also, a wild Ampharos would be awesome.

I was fortunate to find a wild Dragonite as a noob (my son ended up catching her for me, at the time I couldn't throw a ball straight), but haven't seen one since. Would love to see another and catch it myself!

A wild Tyranitar would also be great, and of course Unown, whose existence may only be a rumor.... does anyone here have one?

P.S. I've been very lucky with 5 wild Snorlax, (one on incense in my driveway).

Definitely Snorlax.
Unseen, uncaught, unhatched for me.