Well I'm currently asking a question and couldn't find a tag to specify it..
The simple tag "RC-circuit" would've been a complete description and I'm wondering why those aren't there? When asking about the specifics of those circuits shouldn't they be tagged as such? Or maybe "RC-filter", not sure that's as quickly found though.
Other tags:
"RLC-circuit"
"LC-circuit"
"RL-circuit"