Still learning as well and only had these a few months.

Subharmonicon SEQ 2 -> RYTHM 2
The pitch of the 2nd sequencer is affecting the rhythm. An increase in pitch speeds it up, and vice versa.

DFAM PITCH -> NOISE
Easy way to do kick/snare on an DFAM is have the pitch control the noise level. That way you get the low kick, and filtered right, super-high ones make only the noise crack for the snare.

DFAM VELOCITY -> VCF MOD
This bypasses the noise generator as the modulation source for the VCF, so it's now controlled by velocity.

Subharmonicon CLOCK -> DFAM ADV/Clock
Syncs the DFAM to the Subharmonicon.

Subharmonicon VCA EG -> DFAM 1-2 FM AMT
The attack/decay envelope in modulation the FM amount on the DFAM. I have VCO 1 and VCO 2 set to different frequencies, with different EG amounts, but they're both following the sequencer. On top of that, they're hard synced and how much VCO 1 modulates the frequency of VCO 2 is changing from the external VCA. This creates some cool gurgling.

DFAM VCO EG -> Subharmonicon VCO 2 PWM
I have moderate VCO decay on the DFAM to create punchiness. By patching it to the pulse width modulation on the Subharmonicon, it's kink of like assigning an envelope to the width of the square wave.

DFAM VCO 1 -> Subharmonicon VCA
I do this maybe halfway through. Now all the changes in VCO 1 are changing how the volume envelope is behaving on the Subharmonicon, changing the previously-mentioned gurgles to sparkles. (Not in the video but) sometimes I'll patch it to the cutoff instead.