Nothing is really safe. Maybe an emoticon? IIRC, the use of emoticons was stopped after someone registered the poop symbol on .la.
https://en.wikipedia.org/wiki/Internationalized_domain_name
https://panic.com/blog/the-worlds-first-emoji-domain/
http://xn--ls8h.la/
unicode 1f32e is the taco emoji, so i think I will be migrating all my internal things to http://servername.1f32e
Nothing is really safe. Maybe an emoticon? IIRC, the use of emoticons was stopped after someone registered the poop symbol on .la.