Hello @rodr0p, and welcome to the forum!
There are actually a few gel pens in our forums resource category to be discovered by you.
They can come as a single brush presets, with the file name extension KPP, or as part of a bundle, with the file name extension BUNDLE. In case the downloaded files are archive files like ZIP, RAR, 7Z, 7ZIP, or other archive formats, you need to unpack them first using a so-called archiver program to find the bundle or brush preset file inside (if you need support with such software feel free to ask, but then we need to know which operating system you use). Please do not unpack bundle files, although Krita bundles are in fact a special kind of ZIP archive, they are not meant to be unzipped/unpacked before use, you simply import such a bundle into Krita via:
A bundle is installed in Krita via the menu ‘‘Settings’’ >> ‘‘Manage Resource Libraries…’’ and in the opening dialog you have to click the button + Import in the next dialog browse to the downloaded bundle, select it and confirm the selection. Now Krita imports that bundle, and you can use its content, so the brushes in case of this bundle.
In case this BUNDLE comes in an archive-file, like ZIP or RAR for instance, then you have to unpack the archive to get the BUNDLE-File it contains, then you can proceed as described above.
Loose resources, like single brush presets (gradients, patterns, etc.) are imported as follows:
And single brush presets (not bundled or “loose” brush preset files) are imported into Krita via the menu
Settings>Manage Resources...where you have to click on the button Import Resources, in the opening file manager dialog window you have to browse to the downloaded brush preset file, select it and then import it usually with a click on the OK-Button of the used file manager, usually a double click on the resource file to import works too.
And now to the gel pens you search:
You may want to visit these topics where you can find gel pens, loose as well as bundled ones. If these fulfill your requirements I can’t tell, but you’ll find it out quickly while testing them:
And the only bundle I found with a quick search is this one which contains two gel pens:
Michelist