Blinkies are a small gif, the typical sizing being 150x20 pixels big, and are usually only 2-4 frames. they have a flashing border around them, which is where the name blinkie comes from. They've been around almost as long as gifs in general, you'd see a lot of them around on personal sites inn the late 90s and early 2000s. They started out simple to make and still are, you can make them with almost any digital art platform. Here's a little tutorial on how to make them so that you can make your own.
most if not all drawing software, from MS Paint to Clip Studio Paint, you can make a blank drawing known as a canvas. you'll want the width to be 150px and the height to be 20px.
you'll want to make the design, picking the color you want for the background, adding the text, and drawing* out anything else you want on it.
*Note: if you want it to look like actual pixel art and not just blurry, check your software tools to make sure anti-aliasing is turned off. this gives the pixels a hard edge.
blinkie borders usually are about 3 pixels around the blinkie. the inner detailing is usually 2 pixels of white or some similar light color, 1 pixel of the border color, and then 2 pixels of a different - usually darker - color with another border color pixel before the pattern repeats. Sounds complicated, I know, but here's all it is.
Blinkies are typically 2-4 frames. Some drawing programs already come with an animation feature for free, but if your platform either paywalled that option or simply doesn't have it, you can use a gif maker site and import each frame manually. the border colors switch places mainly, but you can also animate other parts of it too. For this I made the sparkles animated too.