What are some alternatives?
When comparing Unicode-Table.com and PopChar, you can also consider the following products
Event Viewer - Get help, support, and tutorials for Windows products—Windows 10, Windows 8.1, Windows 7, and Windows 10 Mobile.
WinCompose - WinCompose supports the standard Compose file format.
BabelMap - Unicode Character Map for Windows
Gucharmap - Open source character map for the GNOME desktop environment.
AllChars - If you're new to AllChars: start with the Introduction, see the FAQ and Manual. And finally download it. AllChars is now Open Source, usage is free and the sourcecode is available.
Shapecatcher - You need to find a specific Unicode character? With Shapecatcher.com you can search through a database of characters by simply drawing your character into a box. It can find the most similar character shapes for your drawing.