Think of a story, explanation or idea that you want to communicate and make it as a comic.
The tools below have characters you can use, like an alien, for example, text boxes and speech bubbles.
Why not quickly try ToonyToon, StripGenerator or MakeBeliefs to make a one panel or multi-panel cartoon?
Advanced
Once you've made some great work in the tools above, you might want to try these too.
Storyboarder and StoryboardThat are meant for creating full professional storyboards for films, but you might use it for this because it has lots of scenes and props and can export your cartoons as gifs or mp4s.
Cartoons can be used to make someone laugh, or explain a series of events, or even describe an argument from two points of view.
Whether you want to just have some fun, or have some serious fun, comics are worth investigating.
A dissertation in graphic novel form. Beautiful
Here are lots of places to get images that some tools will let you use?
The Internet Archive has a section of
A wonderful collection of older strips, many of which are public domain.
For fun, you might, control(mac) or alt(click) to save them to your computer and edit them with Pixlr to add your own words.
A strange collection of retro comics from Captain Science to The H-Bomb and you.
The issues are downloadable in .cbr format for which you will need a free comic reader like YAC Reader.
Which one of these do you like best?
Although having some quirks, this tool let's you easily add backgrounds, characters and speech bubbles etc, OR use the in-built collection of graphics. Simple, but I like it.
Canva's Comic tool, with loads of great templates is fantastic. Start from a layout and you can drag in your graphics.
Downloadable guide to drawing cartoons and comics.