True stretch 5s that don't tank your defense are incredibly rare. Kleber, Horford, Jackson, Mobley?
There are another group of playmaking 5s like Bam and Green, but most of their utility is on defense and Green's offensive short comings are really going to start to show.
The guys that have the best chance of hitting as valuable stretch 5s are PJ Washington... Naz Reid... then its a lot of guys that might work if you squint a little like Boucher, Bazley, Roby,
I think if they do a re-tool you can use Collins for sure... but you have to pair him with the guys from above and need a good rim protector with him. I also wouldn't mind getting Olynyk or Muscala as a 20 minute a night guy to pair with him.
Mavs work because Kleber is under-rated as a unicorn. Was a rim protector but also was guarding Kawhi a lot last year. DFS and Bullock are great on the wings and Luka is flamable at times but competes and gets a ton of boards... He is also a one man amazing offense when surrounded by shooters. He's as close to unsolvable as a player as there is.
Celtics have maybe the best collection of guys who can defend that I think I've seen in a while. They play like maybe one less good defender.
Jazz will need like 4-5 plus defenders if they move Rudy... I'm skeptical. They need 2-3 if they keep Rudy... I'm skeptical there too. Really curious how we mess this up... I kid... kind of.