If like me, you have a huge range of custom shapes, you can use them with the render menu and flame in Photoshop combined with actions, any of them (unless they are super complex and then the plug-in will generate an error).
The key thing for this tutorial is to create an action and use a shape name 'x_1' or something like that. The action needs to be created via the panel (window menu) and you need to set the right side menu tool recording to be on (not sure why this is not on by default).
As a suggestion, set the background to black by edit menu and fill as I think the effect looks so much better with a black background.
Select the path option with the custom shape tool selected and select a preset from the presets panel. Rename the shape to the aforementioned 'x_1' or something else that is unique. Go to the panel and set allow tool recording to ON. Create a new action and give it a name and start recording. Draw out the vector design as a path (named x_1 or whatever)
Go to the render menu and flame, go with the candle light option but you can try any of them out. Set the jag etc. Set any of the settings that you want such as the color etc. Randomized shape is one of my favourite settings. Click OK.
You can also add in other filters like stylize and oil paint or wave etc. Apply the filters once or multiple times and that gives a lovely blurry / smeary look to your fiery image. All these steps are being recorded and will be applied on any playback. Also perhaps using one of the filter gallery effects such as glowing edges. Perhaps add in some adjustments like levels (great for brightening up the layer) and vibrance.
Stop the recording. You can now delete the existing work path or you could also add that into the steps. Go to shapes panel and rename the vector preset to some proper name and rename another to 'x_1' or whatever you used and now you can go to the panel and re-apply / playback all the steps with the new path and so on.