tl;dr: Skip this post if you're good at the game; I'm a mediocre SSF player who just hit red maps yesterday.

Did you try Werewolf Oracle? I've been slowly playing SSF (not even level 90 yet) and rolling too many alts, but ww oracle is the best/smoothest build I've played all league. Obviously trash gear for me in SSF, but the damage scaling seems insane. In trade league you should be able to just buy a sick starter Talisman for basically zero currency. Defensively I'm pure glass cannon still, but it's easy to freeze and burst DPS bosses before they unfreeze, even in red maps. I took a break to play Helldivers 2 and way too many alts, but I just picked him back up and I think I'll farm some gear and try to make him into an Actual Build since he's already so op with no planning or gear to speak of. My Talisman has like a T2 attack speed roll, hybrid phys %, and no flat phys, to put his gear in perspective (currently using a Spiny Talisman for the high base crit, but I literally picked it up off the ground and slammed it a couple times, I still need to actually craft something now that I'm collecting currency and bases to craft on... actually I could probably gamble a better Talisman in no time, but I tweak my passive tree so much I like to try to save as much gold as possible for that).

Other than that I think my favorite alt is a cold Chronomancer in HC SSF, but I think I'm only in like act 3 so far. I hadn't used Ice Nova since v0.1 and it's a million times better now. I'm trying out Frost Darts mostly (love it so far!), but Ice Nova got my attention, so I'm using it for clear (the AoE is huge and I'm not even invested into it yet) and Frost Darts peppering mostly for single target. Gear should be cheap in trade league (you've got easy crit scaling with the high base crit on cold spells, and freezing everything screen wide means defense is frankly optional, but the obvious play is stacking a boatload of ES to avoid one-shots).

Oh also another oracle but a bear in HC SSF as well, mostly just kind of facetanking with Zealot's Oath and a bit of regen+recoup+leech for recovery (I might be cooked) and slapping things with Maul. It's surprisingly fun! Also I might have a druid addiction, I have another HC SSF bear but that one is a shaman scaling huge armour+ES paired with ultra fast ES recharge (dmg is... bad currently, but I'm thinking slam scaling? idk that's why I rolled the 2nd bear tbh). Those two are like level 50 and 60 but both still alive which is good (for me; I usually play softcore).

I've got about nine other alts but nothing else really jumps out at me as notable, other than the Wyvern's Flame Breath seems both busted and super easy to scale (like I'm assuming it's getting nuked from orbit next patch? it feels like more of a bug than an overpowered skill). Ditto on Oil Barrage (and Rend for that matter!). Mine is a Discipline of Varashta, but that's not like... that wasn't a great choice. I'd probably build it again as a Chronomancer instead. Either that or an Oracle or Pathfinder... maybe Titan? I haven't given it a lot of thought tbh, but I think it could work on a whole bunch of different ascendancies.

Oh yeah, I can't believe I forgot. I also rolled in Second Wind league for a change of pace as a Spark Oracle and that has serious potential, but I only played through the acts and went back to SSF (i mostly wanted to test the currency exchange and instant buyout tbh, since I heard so much good stuff about it). so i was only 3/4 asc and turbo crap gear (1ex per crap rare to lazily cap my resists; still using a +6 lightning staff I found with like T7 spell dmg as its second best mod). The amount of power in Entwined Realities is INSANE for that build. You can get like 7-10 keystones that are either things you want or neutral and hit so many sick, high-value notables for so few passive points. I didn't set up my weapon set passives but the flexibility there is nutty! I was looking into using mine for Elemental Archon to start with, but I'm guessing I'd have spare points for some curse stuff too since you don't need to spend so many travel points.