"Are there other commands which prints only the shell variables, without the functions?"
In man bash, in section SHELL BUILTIN COMMANDS (in the set section) it says: "In posix mode, only shell variables are listed."
(set -o posix; set)
 note: () syntax spawns a subshell, if you don't like forking just use the more verbose version
set -o posix; set; set +o posix