Character Code Champion

Browse, search and bookmark characters in the UTF-8 encoding system. You can view the decimal, hexadecimal, HTML entity and name of each character. It lets you customize the code formats, save up to 256 bookmarks (exportable/importable to and from a .csv file) and choose a dark or light theme.

Please try the lite version before buying.
https://play.google.com/store/apps/details?id=com.grantojanen.charactercodechampionfree

Search and exportable/importable features require Android 4.4 or newer.