Anything that have been covered by a WK book club, especially Absolute Beginner Book Club (ABBC), but also Beginner Book Club (BBC), will have a lot of resources to help: vocabulary sheet and also grammar questions asked and answered. You can find a master list of book clubs here. Here is an incomplete (because it hasn’t been updated for a while, but still good) list comparing the difficulty of Beginner Book Club picks. Although, you’ll probably find more break downs and such in ABBC picks.
Personally, I find Yotsubato (BBC) really funny. It can be a bit hard, especially early on, if you don’t have a good grasp of casual language and its many contractions. I also really liked the にゃんにゃん探偵団 books read with ABBC.
It might help to know a bit more what you like to read to make any recommendations. Ultimately, you’ll probably find it easier to push through some difficulty with something that you enjoy, than something you only read for studying purposes.