These are the four platforms where I have data. I hope to one day move it to a single platform.

Kanban uses the term card, Todoist says task. I use both.

AsanaTodoistTrelloZenkitBeauty5/10 - has a few backgrounds to choose from. Images attached to cards become small thumbnails.❌9/10 - An ever-growing number of pretty backgrounds thanks to Unsplash. Attached images become medium thumbnails on corresponding cards.5/10 - has a few backgrounds to choose from. Images attached to cards become small thumbnails.TagsColored background and globalColored font and global; paidColored background and siloed per boardColored background and siloed per board; can have multiple categories. Can be used to color the whole card. See below.Descriptions☑️❌☑️☑️AttachmentsCan be attached to cards or commentsCan only be attached to comments; paidCan be attached to cards or commentsCan be attached to cards or commentsRepeating tasks☑️☑️❌ - Power-up. Appears on due day.☑️Reminders☑️☑️❌☑️ - Added as a separate field, but you can add many such fieldsLinks between cards/boardsPaste the URL yourself.Paste the URL yourself.☑️ - Add it as an attachment. No URL pasting requiredPaste the URL yourself.

Zenkit does really interesting things with tags that I think are worth addressing in greater depth. You can have different batches of tags. For example, each task might want a group of tags that refer to its location, then a separate group of tags to represent times of day.

It doesn’t make a distinction between a list heading and a category, so you can see the tasks organized by any batch of tags. Let’s expound on the list above with the two batches of tags. Suppose your headings are the classic to-do, doing and done. You created the two batches of tags described above, but the column heads are a third batch. By default, I walk in and see the do-doing-done columns. I can choose a filter and organize it by time of day, then the do/doing/done columns will appear on the cards like any other tag.

Another interesting thing it does with tags is that it’ll let you define a batch that will color the task itself. Again, suppose you want your morning tasks red, midday, orange, evening, yellow, and night, green. There’s a setting where you select which batch of tasks you want to define the color of the cards. If there are multiple tags from that field applied (say something can be done morning or midday), it guesses which color you want.

I think Zenkit is the most interesting, but it’s missing global tags. I recently turned my attention from it to Todoist, which is a little like going from a luxury car to a compact sedan. I may be able to split the difference with something like Zapier or IFTTT.

Asana also has global tags, but there are a handful of features the other three have that it lacks. The one that comes to mind is that you can’t copy lists to other boards, you can only copy whole boards.

The reason I’m so hung up on this global tags business is that I always have like 30 boards going. If I have a couple hours off work during the middle of conventional working hours, I want to easily pull up a list of all the things that can only be done during hours I’m normally working.