serpentry

Ever17 and I/O are my suggestions.

Exactly this. Silvz is probably right that you should read Higurashi first. You can completely understand Umineko without reading Higurashi. But Umineko does build upon certain concepts that got started in Higurashi. They are both really good, though I think Umineko is a bit better.

Read Higurashi first, then Umineko [no naku koro ni]. Hiigurashi starts as a Slice-of-life, but it has a twist!
If you liked Grisaia, you should definetely read KEY games [Clannad, Little Busters!, Kanon, Air, Summer Pockets, Planetarian] as they are the masters of nakige/crying games.
For the mystery part, you could play 999 [and its sequels VLR and ZTD], Infinite Series [Ever17 is the second of it], AI: The Somnium Files [not a VN, but very good mystery hybrid] and if you want mystery with a lot of good humor and plot twists, read Danganronpa [1, 2, spin off, the anime-exclusive story then V3]
 

I guess Umineko would be mandatory in any mystery/detective request.
Ever 17 is also a great mystery VN although some fantastic elements might disappoint 
G Senjou no Maou has a great protagonist and an excellent main route. The other routes are not as good and certainly not mandatory since they abandon the mystery, just play the main route that is the canon true ending
 

Chaos;Child is great for mystery!! Mc is not very strong but as a muder mystery it was so good.

For the recommendation, I guess I can recommend Baldr Sky duology and Galaxy Angel trilogy if you didn't mind with sci-fi. Also there's Evenicle as well, and if you didn't mind partially translated VN you can try Amayui as well (Currently the narration was at 63% translated). I don't know if you already play those VNs or not, but if not then I hope my recommendations here could be helpful to you.

You might like some of Eushully's strategy games but I don't know that any of them are fully translated.

Tears to Tiara I and II. Only played II, though, so would rather recommend that one. (can be played without the I)

Edelweiss has a teacher route, pretty funny and lighthearted game.

Hello everyone.

Before going into the project, here's some information regarding the game:
- Kami no Rhapsody (https://vndb.org/v16341) is a VN/SRPG hybrid by the company Eushully, the same company that made Kamidori Alchemy Meister.
- Sypnosis (taken from VNDB, with some changes made to go with our translation patch):

Translation team: Rhapsody Translation
Team Members:
 - Translator: FlamePaladin
 - Translation Checker: Danywar, Dark_Gamer
 - Editor: Vuken, Yuuko Shionji
 - Image Editor: Nylios, hubb2001, Bilbael, pegg
We have a full team atm, but if you want to join us, please send me a message or post in this thread. Thank you ^^.

Special thanks:
- Huang Yin Ling and maefdomn for their very useful threads.
- binaryfail for helping me find the tools to work on this patch.
- SaintLouisX, asmodean and Aroduc for their tools.
- Special thanks to Kirashi for motivating me to work on this patch, and for the feedback. I really appreciate it.
- Special thanks to Mr Poltroon for your work as an editor in this project. Though it was short, I really appreciate your help ^^.
- Special thanks to Danywar. Thank you very much for joining the team as the Translation Checker. I'll be counting on you a lot from now on .
- Special thanks to glupak. Thank you very much for everything you've done for the project. I really appreciate it ^^.
- Special thanks to Vuken. Thank you very much for joining as our Editor. Tbh, I don't even know if you're in this forums lol. In any case, I'll be counting on you to make our patch readable XD.
- Special thanks to nylios. Thank you very much for joining the team. I'll be counting on you for a lot of things, so prepare yourself .
- Special thanks to hubb2001. Thank you very much for joining us as our image editor. I'll be counting on you for the images XD.
- Special thanks to pegg and Bilbael. Thank you very much for joining us as our image editors. Let's do our best to make the complete patch a reality! XD
- Special thanks to Yuuko Shionji and Dark_Gamer. Thank you for joining as our TLC-er and editor. Let's make this patch the best it can be XD.

Finally, here's the link to the full patch:
MEGA link: https://mega.nz/#F!MstRHI6S!bQVaRTSLnwQPNjYuCJKfpw
The full patch has been released. However, there are still some minor texts that I couldn't find, so they're still untranslated. With that said, they're just some minor texts and won't impact your experience with the game.
Do note that our patch does not include any of the game updates, so you'll have to update them separately. All of the game's updates and appends are translated in our patch though.
Now, with the release of this patch, we won't be focusing on KnR anymore. The patch also won't get update unless there are some game-breaking bugs. Instead, we'll now focus on our other projects.
With that said, please contact us if you encounter crash or any other problem. We'll try to fix it as soon as possible (and if it's related to our patch XD).

This is everything from me for now. If you took your time to read that wall of text, thank you very much. Even if you didn't, thank you for showing enough interest to click on the thread.

See you!