architect
writer, nonfiction
writer, fiction
poet
painter
musician <-- theoretically you wouldn't even need to do live performances, especially in the electronic genres
illustrator
photographer (specifically of non-human subjects)
freelance website creator
graphic designer
craftsperson (see Etsy.com for examples)
eBay seller
home stock market, etc. trader (I know nothing about this)
translator (written documents)
programmer/application developer (I know nothing about this either)
text writer for websites (person who writes product descriptions, etc.)
engineer
researcher (depends on the field. of course. Usu. univ.-funded)
though)
Job at bookstore/library that by hours/location does NOT require customer interaction (stocking/reshelving, etc.)
antique collector/dealer (if you could find someone to share your enterprise with who will do the client interaction might be good)