Ahh got this one.
http://www.mangago.zone/read-manga/dear_benjamin/
http://www.mangago.zone/read-manga/master_drifting_away_again/
http://www.mangago.zone/read-manga/ai_o_ataeru_kemonotachi/
http://www.mangago.zone/read-manga/a_mild_noble_s_vacation_suggestion/
http://www.mangago.zone/read-manga/funouhan/
http://www.mangago.zone/read-manga/tomodachi_game/
http://www.mangago.zone/read-manga/mashle_magic_and_muscles/
http://www.mangago.zone/read-manga/jinrou_game/
http://www.mangago.zone/read-manga/again_my_life/
http://www.mangago.zone/read-manga/tensei_kenja_no_isekai_raifu_daini_no_shokugyo_wo_ete_sekai_saikyou_ni_narimashita/
Okay.. there are some females mixed in there, but most are emotionless or smart, and perhaps even both. I'll explain some.
1. bl both are strong. involved with some illegal fbi shit
2. comedy. strong x cluess Technically doesn't fit description much, but please read it. it's good. female mc
3. Emotionless female mc who is crossdressing as a boy. smart and strong.
4. Reincarnated semi-emotionless mc. smart and powerful. kinda isekai? Male mc
5. Killing. Assassins. Technically emotionless and smart. I heavily recommend. male mc
6. Killing game. betrayal. Smart male mc stuck in a killing simulation
7. Epic. Emotionless but a little dumb. Powerful mc without magic. Black Clover in a nutshell. Male mc
8. Killing game w/ 3 consecutive books in the series. 1st one is shit. Female mc who is smart and later becomes emotionless.
9. THE MOST EPIC. Not emotionless, but a very smart, powerful mc, who reincarnated after being killed. About lawyers and prosecution Male mc
10. Isekai. Powerful and Emotionless mc. Reincarnation Male mc
Also, it seems like you might have the same tastes as me, so i'll give you my list or summ.
http://www.mangago.zone/home/mangalist/1030948/
Thanks!(⌒▽⌒)
Can someone please recommend anything where the protagonist is cunning/smart and kinda expressionless or calm?