HDL Checker
Repurposing existing HDL tools to help writing better code
...It supports Language Server Protocol or a custom HTTP interface; can infer the library VHDL files likely to belong to, besides working out mixed language dependencies, compilation order, interpreting some compiler messages and providing some (limited) static checks. Notice that currently, the unused reports has caveats, namely declarations with the same name inherited from a component, function, procedure, etc.