I won't give you any specific problems, but I would suggest two ways of finding them:

a) take tag 'implementation' in the problemset — many of problems here might be relatively easy for you (like div2 / 1A / 1B), but there are also many problems that require some careful coding — you can choose the appropriate hardness by looking at the number of people that have solved the problem and binary-search the best level for you to train on :)

b) other option would be to open a random CF round and take 1D/1E problem — think for a while and try solving it, but if you don't manage to do it, then read editorial and do your best to implement it. Many of these problems are not easy to implement, so you will not only learn some new techniques, but also improve your coding skill. But remember- implement it, no matter how ugly / difficult it is.