Quadrax is excellent and can self patch in some interesting and fun ways (LFO at audio rate, amplitude modified by a second channel, wave shape wobbled by a third, and pitch affected by the drunken walk alternative mode of the LFO in the 4th channel for example)
Distings is great to fill a gap, but you already have O_C and effectively 3 channels of distings feels overkill / too much choice. If I'm using distings I've exhausted every other way of doing it because the menu on the MK4 is infuriating.
A filter with a variety of modulation would give you more to do with your sound. Steve's ms22 is well regarded and only 4u.
Personally I just don't get on with plaits, I keep going back to it and trying again and again. But it's difficult to tune and whilst very multifunctional, doesn't give me the same joy as something like the twin waves or even the godspeed, (recently I was even enjoying pinging a self oscillating filter through fx more than plaits) and rings does all the interesting modes better. The bastl pizza is also very hot at the moment and worth a look.
I love beads... But also check out the happy herding fx aid... If you happen to find more u to play with