...so, do you mean the particle texture, i.e. the image of the particle itself ?
Assuming I understood your question, a particle has 2 channels: Diffuse and Opacity that you can edit in any image editor.
Then, each particle has 4 "life" keys, where you can assign additional variations.
Finally, a good particle effect seldom is made with 1 single particle: you can create multiple versions and play with the emitter on/off to create the needed variations.
Hint: attach a particle to a dummy in order to easily duplicate it
Did I got your meaning and answered ?
OS: Windows 10 Pro English 64-bit / CPU: Intel i7-9700 3.6GHz / MB: ASUS ROG Strix Z390 RAM: 32GB DDR4 2.6GHz / HD: 2TB+3TB / SSD: 2x512GB Samsung 860 EVO /
VB: Palit GTX2080 TI GamingPro 11GB / AB: embedded in the MB and VB (audio from the VB with an HDMI splitter) / DirectX: 12