First things: this is meant to be an PSA post, not a flex. Just throwing in my thought process on R3 progressions. I play relaxed AQ/AW and concentrate on quests and BGs.

Above are my R3’s as of today. I see a lot of posts asking about this champ or that, so I thought I would start a thread with an attempt to explain my own choices in sequential order.
I currently have materials for 4 more (one will be mutant and one cosmic), but I’m currently waiting to see where content goes. Others are welcome to join in—explanations please if you do.
1.
Wong (L40): My first R3, and a champ I play not as often as I should. I got a mystic gem from Necro completion, and at the time, he was my only awakened mystic and I figured I’d use him for explore. Quest king, not much for BGs other than an occasional defender.
2.
America (L40): My second R3, and I wound up having materials for her and became enamored of her ability to dominate so many modes. She’s been amazing in BGs, great for high-end content and wrecks quests. At the time, I didn’t have any other class I could R3. Great in every mode.
3.
Black Cat (L60): Perhaps my favorite R3 of all. Just incredible AAR and DOT, plus the fluid play style fits how I like to play the game. Monster attacker in BGs, Quests, anywhere. Closest next choice for me was Mantis or Elsa, but in the end it was no contest—and I have zero regrets. My cats were ready and waiting for the Cat—best attacker in game in my opinion.
4.
OGIM (L45): A tougher call—Shuri was R2 and does a tremendous amount of work for me. Two-way threat in BGs, counter for annoying defenders, huge crescendo DOT damage. I chose OGIM because he’s also a monster—ability to take a lot of blocked hits and dish out a ton of damage. I needed a Tech at R3 and struggled with this one. Dark horse candidate was Shocker, who sat at R2 and L20. Ultimately, the combination of OGIM abilities (Invalidate, Regen, block Unblockable, Power Lock) won him a spot over Shuri. Great quester, solid BGs.
5.
Quicksilver (unawakened): This was purely an Omega Events decision, and I may have missed the mark with this one. I wound up with awakened Mole Man, OS, Corvus as competition, and I probably should have picked Mole Man. I was in a fog from not pulling Longshot, and I spent a lot of time deliberating. I eliminated Corvus first, simply because I felt like the game was a little past him. I already had a large Skill roster and figured I could still use Mole at R2. It came down to OS and QS, and realistically I feel like I might have picked better if I chose OS. I like QS a ton, but he’s a bit of work for things like BGs. Ah well…
6.
Silk (L40): Silk got passed for Cat and others a couple of times—not because I don’t love her (she’s a close second for favorite attacker behind Cat), but simply because I felt like she didn’t need R3 to wreck stuff. I again stared down Elsa, Mantis, Shuri, Bishop and picked Silk—mainly because of her silly damage and auto evade. No regrets—she rocks everything as attacker.
7.
Ham (L60): Why Ham? He’s a beast—lots of use two-way, ability to stretch BG fights with poppers and the ability to crush annoying mystics via poppers/taunts. Add his evade and unblockable and use as a current Saga champ and it was a pretty easy call. He’s a phenomenal attacker and sneaky defender.
R2 Short List: Bishop (L80), Domino (L50), Vox (unawakened), Serpent (unawakened), Guardian (L100), OS (L20), Venom (L20). My next 2-3 are among these, and I’m really just biding my time to see what’s next. If I think I need one at R3, I can do it—but I’d honestly have to push an Onslaught, an awakened Serpent, or a few other Titan pulls to top of list.
Hope this helps players facing tough decisions. Feel free to add any of your own insights to this thread.
Dr. Zola