MaruMori

Pros

• If you want an All-in-one use Renshuu App/Website or runner up use marumori.io
• MaruMori: General reinforcement, grammar, and vocab
• Currently, aside from the Shinkanzen textbooks, the only grammar resources I recommend for my students are Marumori and imabi.
• Duo barely teaches grammar concepts, whereas MaruMori actually has lessons on grammar concepts.
• I personally have been really amazed and am a huge proponent of the marumori.io site, they've got a nice little package with some truly amazing grammar explanations.

Cons

• MaruMori has been known to use scummy marketing tactics on this subreddit to try to farm traffic to their site. It also happens to suck... MaruMori is just selling you the illusion of progress, kind of like duolingo.
• I didn't click with Marumori. Their lessons are solid, but I found their vocab/Kanji srs to be lacking. You unlock big lists at once, that you learn without context. It took tremendous effort to make words stick.
• I tried it and didn't really click with it, in particular I didn't really like the UI. It still looks like a good resource, and they offer a 14 day trial.
• I know Marumori has conjugation drills but I've never used it so I don't know if it's exactly what you're looking for.