This page is unfinished and unlisted, so you weren't supposed to see it yet, but it you have, remember to take the facts that are here with a grain of salt.
Go on, take it. Save it to your hard drive. Add it to your own collection.
File Collection
People collect all sorts of things. I probably would like to collect stuff, if I had an excess of money and space, but things like image files or free PDF's are usually free to download and take up very little space, (the majority of my images are less than a megabyte large, and I have exactly one PDF in my main collection that exceeds 100 megabytes,) so that's what I collect. This page has some info on how I do it and how (and why) you should do it too.
Disclaimer
This page is not about piracy in any way, and contains no information on how to illegally obtain copyrighted works (except for, like, general instructions on downloading things, like clicking "Save Image As...") If all you want is a mountain of drawings or memes to look at, or more PDF's than you can hope to read, the internet has those on tap - clean, legal taps, not grimy, rusty, illegal taps.
Now that that's said, let's get downloading.
Drawings
Drawings are the main thing I like to collect nowadays. I download them so I can admire them offline later, but I also learn things from them: I learn about all kinds of different styles, or different ways to draw things and characters. My good-drawins/ folder is 342 files strong at the time of writing this.
Here are a couple guidelines and practices I follow when downloading drawings:
1: Check for permission
From what I understand, it's considered free use (at least in the U.S.) to download images for personal use if they don't have a name on them [fact check please] and it's not explicitly stated to be prohibited to do so. If there is a name on one, I check the user's account to see if they give permission for personal use. Artists will often have an FAQ or a Carrd where you can find an answer to that, but if not, I look to see if they've stated that in any posts.
On sites like Twitter or Deviantart, that's probably really hard to do, but on Tumblr, you can just go through the archive and filter for asks only. I find that "icon" is a useful keyword to search for, since people usually will be asking for permission to use it for internet profile icons.