I think you're on the right track with the Disting - sequencing, random, and modulation would definitely expand your rack's functionality tremendously.
If you're into DIY, I think the biggest bang for your buck would be an mxmxmx Ornament and Crime. The O_c has two dominant firmwares at the moment: the default one, which allows it to act as a sequencer, source of random, quadrature LFO, complex envelope generator, quantizer, and a couple other things, but usually one item at a time. The hemispheres firmware cuts down on the scale of these features, but adds a ton of different utilities, and you can run two at once. I have one for each firmware, and they always come in handy. Pusherman has a bunch of kits, including a full (chonky) through-hole kit, and a micro kit with all the surface mount pieces already soldered.
For the glitch effects, I'm not sure if there's currently a good DIY option for that sort of thing, but the QuBit Data Bender sounds right up your alley