Looks like you missing the toilet-fonts package.
sudo apt install toilet-fonts
The fonts are there:
$ dpkg -L toilet-fonts | grep tlf
/usr/share/figlet/ascii12.tlf
/usr/share/figlet/ascii9.tlf
/usr/share/figlet/bigascii12.tlf
/usr/share/figlet/bigascii9.tlf
/usr/share/figlet/bigmono12.tlf
/usr/share/figlet/bigmono9.tlf
/usr/share/figlet/circle.tlf
/usr/share/figlet/emboss.tlf
/usr/share/figlet/emboss2.tlf
/usr/share/figlet/future.tlf
/usr/share/figlet/letter.tlf
/usr/share/figlet/mono12.tlf
/usr/share/figlet/mono9.tlf
/usr/share/figlet/pagga.tlf
/usr/share/figlet/smascii12.tlf
/usr/share/figlet/smascii9.tlf
/usr/share/figlet/smblock.tlf
/usr/share/figlet/smbraille.tlf
/usr/share/figlet/smmono12.tlf
/usr/share/figlet/smmono9.tlf
/usr/share/figlet/wideterm.tlf
Another issue can be if somehow toilet was using another directory for fonts, force the right directory with the --directory (or -d) option:
$ toilet --directory /usr/share/figlet/ -f ascii9 Ubuntu
m m # m
# # #mmm m m m mm mm#mm m m
# # #" "# # # #" # # # #
# # # # # # # # # # #
"mmmm" ##m#" "mm"# # # "mm "mm"#