Tags
On GoodTask, you can use tags with any symbol and any text. The key is on Smart Lists and Quick Actions.
Tags on Smart Lists
While adding a new Smart List, add a 'Filter' with type 'Text'. Select 'Include' and type in whatever tag you'd like below (i.e #tag, @home).

You can use multiple filters to include or exclude multiple tags on Smart List for powerful use. For example, you can make a list that shows tasks with #later tag and hide tasks with #hide tag. Or you can show tasks that include both #work and #today. It's flexible and powerful
Tags on Quick Actions
To add/remove tags easily on tasks, you can use Quick Actions. First set your preferred option on 'Settings > Preferences > Tag on' to choose where your tags should be at. Normally it's on notes field.

Inside 'Settings > Quick Actions', you can use 'Tag' type and 'Switch' type to manage tags.
'Tag' type lets you add/remove tag at one touch. 'Switch' type lets you switch between multiple tags including an empty tag.
You can type in '#tag1 #tag2' in 'Tag' type to put in multiple tags at once if needed.

