There's no tag dictionary on mangago (there's one on Baka Manga Updates though), but you can search by this http://www.mangago.me/tag/ just type any tag you want.
Yes, input any tag after the link helix wrote there. If there is a tag including 2 words, replace the space with + (example: 'innocent uke' should be written 'innocent+uke')
Click on any manga, scroll down and click on one of its tags. Then it brings up a screen where you can search other tags.
Oh, yeah, good point! There's also this small box on the right, where you can just type a tag.
Where can I find the tags list? I want to find the sort of manga I want with tags but I can't find tags. Please help me.