This code should work, assuming you wish to list user-entries who have both b and B (use the binding from the initial post). If you rather want a listing of user-entries that have either b or B, replace the & with a |
proc request:bots {nick host hand chan txt} {
puthelp "NOTICE $nick :Here is a list of my requestable bots:"
puthelp "NOTICE $nick :[join [userlist bB&] ", "]"
return 1
}