Is there a Eurorack module that could serve to add an arpeggiator to the Oberheim TVP?
As you might imagine, there are lots of ways to go about it, depending on your needs.
(1) You could buy a dedicated arpeggiator module. Blue Lantern makes an inexpensive one, and there's an arpeggiator built into Pittsburgh Modular's current MIDI interface. Or you could spend a lot for a Flame Arpeggiator, but they're hard to get in the U.S.
(2) Or you could take a more modular approach and combine an LFO and attenuator with a good quantizer, like the Intellijel µScale II, which lets you make custom scales.
(3) Or you could get a sequencer with a built-in quantizer (see the Qu-Bit Octone, which I used to have and can vouch for its awesomeness), dial up arpeggios, and use a unity mixer to transpose the pattern.
(4) Or you could combine a non-quantized sequencer with a separate quantizer. René would be a great choice here, but there are zillions of less expensive choices. This is similar to (2), but allows you to get by with a cheaper quantizer. As with (3), you can transpose with a unity mixer.
(5) MiniBrute!