How can i make a low poly flame animation in Blender my computer is not exactly advanced and i really need some low memory usage SFX that can be exported quite easily for the game engine without many memory leak.
(and yes if you want to ask what game engine i use to make games it is Godot Game Engine)
i would really appreciate it if there's anyone that can give me some clue or maybe made some tutorial for me (wishful thinking intensifies) or maybe pitch in some idea if you don't know any method for this problem.

Thank you :D
I took a quick stab at this with a Sculpted mesh using Dynotopo symmetry off with a pixel setting of 12.

The rest was done with just animating an empty, and using that empty as the referenced object in a displacement modifier with a magic texture.

This was about 10 minutes worth of work if you happen to be efficient in Blender.

Hence I'm sure you could spend a little more time if you want it to look as good as it does in your reference.

I would imagine that an animated loop of upward flying diamond shapes at the same speed and the same material would sell the flying ember effect.

Here's the fruit of my 10 minutes (the difference between the two are texture selection &amp; empty animation differences only):

Attempt #1:


Attempt #2:




Per request here is the Blend File:
I've also included an action within it for you associated to a "Fake" user.
As of Right now, the animation wont start until you hit frame 15.
In the NLA editor just drag the action back to the beginning frame (highlight it and hit G >> Drag to the left) to watch the full animation from the start.

As for a sprite sheet, I really recommend watching the video I linked to in the comments. 

Here is a Sprite sheet that I rendered out from this file: