I am wondering what lenses you would recommend that work best in both dark environments and for landscape. I have a Canon EOS Rebel T5, and I'm just looking for something to capture mostly the moon and other landscapes.
If you want to take the picture in one shoot, I'm sorry to tell you: Forget it. If you can see nice scene does not mean you can shoot same scene too.
If you are willing to "photoshop", you are about to take several shoots in as high cadence as possible to catch nice stars, moon and landscape. Then merge them in one. Be ready to capture tens of RAW images.
85 % of the work rely on your skill, 10 % on your luck and 5 % on your gear.
I haven't answered the question, have I? I haven't because when you will get skilled to get all from you, you'll know what lenses to use.
tl;dr: Look for lenses with lowest f-values and try, try and try with the lens(es) you allready have.