PowerShell yet again proves itself to be an enlightened language:
PS> ${Valid characters for an identifier? Eh, ¯\_(ツ)_/¯ whatever (`}) you want.} = $True
PS> ${Valid characters for an identifier? Eh, ¯\_(ツ)_/¯ whatever (`}) you want.}
True
Jesting aside, I have actually used that syntax before to prefix variable names with '&' and '@' to differentiate between virtual and physical addresses in some code for patching a binary.