It's mainly for RTK, but you can add whatever kanji you want. There's a section where you can type your own definition or mnemonic.
If you make an account, just go to the manage flashcards page, then go to custom selection. There you can paste the kanji you want.
Hello! I wrote a userscript that lets you save words in a list for reference in the future. You can install it from here:
https://greasyfork.org/en/scripts/377040-save-favourite-words-jisho
Once installed, when you are logged in, a link "Add to my words list" will appear in the on the links section of a word. Click there to save the word. To consult the list of saved words, click on your username's link at the top right corner.
You can also download the list of words, I advise you to do so from time to time so you don't lose it, because as of today the words are saved in the brower cache accessible from the userscript. Also take into account that the script works locally so it is meant to be used always from the same computer or phone. You won't find your words synced accross different devices.
You can find more info and discussion in this old thread: https://jisho.org/forum/53b4ae046e73347cb6e80100-option-to-save-words
Cheers
Saving bookmarks in Jisho/other apps ?
Is it possible to save Japanese words/kanjis, etc. as bookmark in jisho.org ?
If not, is there any other similar app (which gives same quality as jisho & provides bookmarking facility as well ! ) ?