Considering that I have Rings, Ears (not really useful but..), Plaits and 4ms Listen I/O with Doepfer 1-190-3, and I want
to order Veils and Maths.. What should I put next to get that modulated, long ambiances. Or ambient noises, foggy chords in the atmosphere of Silent Hill, Twin Peaks etc. ?

veils and maths - check - don't slouch on the veils - pre-order from somewhere that is still offering them!! they will be gone before you know it, once the last batch appears

next I'd go for a decent sequencer and a matrix mixer...

for a sequencer I'd go for an Erica black over Rene - rings will take one channel and if you want to sequence chords on plaits, then you'll use another 2 - this will leave one over for the future - always a good plan - and with the black sequencer you can tie notes and you get another track on each channel for modulation as well as the pitch and gate...

matrix mixers are incredibly useful for taking copies of modulation sources and deriving more related complex modulations from them, amongst other things...

"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia

Utility modules are the dull polish that makes the shiny modules actually shine!!!

sound sources < sound modifiers < modulation sources < utilities