Can ya do searches via rating? In other words, can ya pick rating in searches? Thank you!

Yes
rating:safe
rating:questionable
rating:explicit
You can search based off of other criteria as well
https://e621.net/help/cheatsheet

Protego said:
Can ya do searches via rating? In other words, can ya pick rating in searches? Thank you!

Here is a list of all the ways you can search by: https://e621.net/help/cheatsheet#Searching_Post_Metatags

In specific you can customize your searches by rating using any of these:

rating:safe
rating:questionable
rating:explicit

rating:s, rating:q, and rating:e also work.

(To search for posts that are rated safe, questionable, or explicit.)

Just wanted to say thank you guys for linking the full cheat-sheet instead of just giving the answer. Many people have no idea just how many ways you can search for and order stuff on the site, and it helps knowing there's a reference you can go to if you ever need a reminder.