My Answers:
- Plain Strings (207) - foo
- Anchors (208) - k$
- Ranges (199) - ^[abcdef]*$
- Backrefs (195) - (.)([^a]).*\1\2
- Abba (190) - ^((?!(.)(.)\3\2).)*$
- A man, a plan (168) - (.)(.)(.)?.?(\3?\2\1)$
- Prime (201) - ^x(x*)\1$
- Four (198) - (.).\1.\1.\1
- Order (198) - ^.....[^e]?$
- Triples (561) - [031][0][3694]|[053][126][25]|[7][14][4]|^0*$|217|422|895|914|177|734
- Glob (349) - err|lle|tud|ogi|ide|ris|hob|ney|orl|tef|igh|ark|tog|rom|ial|ppe|der|thw
- Balance (267) - ^((?!<<>>>|<><>>|<<<<<<)<(<>|<<|>>|><)*>)?$
- Powers (63) - ^(((((((x|xxxxxxxx)\7?)\6?)\5?)\4?)\3?)\2?)\1?$
- Long count (192) - 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 111
- Long count v2 (212) - 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 101
- Alphabetical (265) - te [ea][aes][sr]|st ar|nt ass|rn re|at en|(ne|et|ar|ta) te|(st|er) sn|ee ta