Well, I personally think the idea of using eurorack just for "experimental noises" is a very limiting and unmusical use for the true extant of its possibilities, but even if that was your only goal, I can make a few recommendations:
1) As an alternative option to the PGH SV-1, I'd recommend the Studio Electronics Tonestar. I think it's more interesting and the quality of their equipment is better than PGH as well as 95% of other eurorack manufacturers. Also smaller HP.
2) I see you already have Quadnic in there..in reference to #1, you might instead try a wavetable oscillator, especially for crazy sounds. The new Erica Synths Wavetable VCO looks great, but there's others, particularly morphing terrarium.
3) #2 Could just as easily apply for Clouds, which seems to me one of those "try to do a lot of things OK" module a lot of people seem to buy and then sell within a few months..so..
4) If you want to play anything other than your self contained voice (SV1), you will need VCAs and envelopes, which you currently have 0 of.
5) If you really only care about experimental drones etc. perhaps this does not matter to you, but you also have no sequencer or quantizer of any kind, thus no way to play notes, music, etc..for me, this is THE most important thing of any eurorack setup or synthesizer, since it dictates the control voltage, which is after all, what this is all about
6) Speaking of which, you don't really have any modifying voltage sources of any kind, it's all pretty much audio. If you don't have voltage out-modules you're missing most of what modular has to offer and you might as well use a keyboard synths or two. My sequencer is the Stillson Hammer Mk2 which accomplishes #5 and #6 in spades. I love it. But you'll need a bigger setup to make it worth it. I recommend not starting with any less than a 104 HP skiff. Make Noise makes a good and cheap one.
Good luck!