Lots and plentiful, here are just some that came to my mind:
Jammer - He is one of the most mindful, musical and awesome/improbably cool sounding contemporary jawropping SID musicians. Period.
Kjell Nordboe - He left behind one of the most multi-dimensional SID heritages ever. You can find every possible and some of the most impossible SIDs there. He passed in 2005.
DRAX - If there will ever be an album called "aesthetics and SID", his music would be 80% of it. An awesome composer in any aspect.
Fanta - I would be surprised if uncle Fanty was unknown to you. His releases tend to set the bar higher every time.
Intensity - With one foot in trance and the other in rock, his heritage contains some of the catchiest post-2000 SIDs. Sadly, his lifework is unfinished due to his unfortunate death in 2011.
Randall - He is a man of catchy melodies and experimentation. The two usually don't go well but check his tunes to see this mixture is working fine.
Wackee/Waczek - If you're into non-compromising ambient and heavy music, he is the man as he is a master of movie theme-like super-pressing atmospheres.
Ne7 - He has a partly avantgarde, partly minimalist stlye that work awesome in concept demos. Check the music collection "Manifold" to get into the feel.
Hermit - Mixing elements of jazz and funk, he is an open minden melodist as well as a master of SID because he is also the coder of the newest native SID tracker, SIDwizard. It has MIDI converter, fluent workflow and distinct AMISH colour mode - what else are you waiting for? Go composing SIDs!
http://noname.c64.org/csdb/release/?id=112716
Conrad - One of my personal favs and an another jawdropping composer for me who never fails to amaze.
G6G - Glenn is a perfectionist. Elgance and always the best sounds. Also, with Geir, he is the developer of one of the most powerful SID tools, SDI (Sid Duzz It)
Geir Tjelta - the brother-in-arms of G6R. Unfortunately now'days he composes relatively few SIDs but if you check his contribution to Richard Joseph's tribute C64 demo, it's one of the most amazingly constructed SIDs of the last decade.
Linus - A true melodist, he is a cross between old super-catchy style and modern sounds, causing some of the most memorable SID moments of the last era, making him one of the most appreciated SID musicians around.
Taxim - We have one thing in common, mixing guitar riffs and SIDs. Taxim often uses samples to add some extra raw edge. He is also one of the pioneering SID remixers ever.
Richard - Mr Bayliss is a man of trance and a creator of hundreds and hundreds of SIDs. If you're into the stlye you'll find a lot of great tracks among his tunes for sure.
SIDwave - Jan was one of those who started HVSC. An awesome composer with his own distinctive style and sound
Fredrik - Influenced by medieval music, Fredrik is probably the closest to a '80s classic game composer in the present scene. I'd recommend to check his 2010+ music as his entry year was mostly about spreading his wings.
I'm off typing now but really, there are so many awesome ones now'days. Just check the latest "Highscore Power Ballad Compo" and listen.
http://noname.c64.org/csdb/event/?id=2028