I've used Pocket from back when they were called "Read it later" and have saved just shy of 30k articles. They've gotten worse recently, but when I tried other apps (instapaper, getmatter, raindrop, paperspan, omnivore) they all had their own issues. Now I have to give those apps another try...

Try Reader from Readwise. It's a great multi platform app which supports all kinds of reading mediums and can save articles, tweets, YouTube videos etc. It's a paid app, but well worth it. Look for comment from tristanho, the founder, below.