Here is the list of some of the good tutorials written by codeforces users :-
- DP on Trees by darkshadows
- Algorithm Gym :: Data Structures by PrinceOfPersia
- Everything about Segment Trees by PrinceOfPersia
- SOS DP by usaxena95
- Invariants and monovariants by TooNewbie
- Z algorithm by paladin8
- Mobius Inversion by Nisiyama_Suzune
- Dirichlet convolution by Nisiyama_Suzune
If you know some good tutorial on codeforces which is not in this list please mention it in the comments I will add it in the list.