ISPs still have data caps?

That should be outlawed by now.

You could:

• Ask your neighbor if he has unmetered Internet connection and if so, then chip in (⚠️ This may be against their operator's terms of service. Before doing so, please check the terms of service)
• Ask a friend with unmetered connection to download all the stuff for you and just hand you the disk
• Use a public hotspot (such as McDonald's Free WiFi) to download this stuff. Take into account that the download speed will be extremely slow.
• Rent a server in the datacenter (i.e. VPS), download the data there, and get the data using your connection only as much as you need at the moment. The disadvantage is that you don't really own the data stored on this server.

This is very technical but if your ISP has unmetered Netflix or Spotify you could have a VPN on a server that spoofs the hostname (easier) or IP (harder) which only works for downloading and i imagine using >50GB of data to Spotify might make the ISP ask some questions. Netflix would be easier since 4k movies are a thing

The easiest/safest way would be to adjust your plan, even though it would cost a bit more and feel kinda shitty. I'm pretty sure they offer an unlimited bandwidth "upgrade" for residential plans at like $10-15/mo, and all business plans should be uncapped.

You could try to spoof your traffic somehow, but I could never get that to work reliably when I had caps. And the overage fees were worse than just paying ahead of time.

https://github.com/ValdikSS/GoodbyeDPI

This software designed to bypass Deep Packet Inspection systems found in many Internet Service Providers which block access to certain websites.

It handles DPI connected using optical splitter or port mirroring (Passive DPI) which do not block any data but just replying faster than requested destination, and Active DPI connected in sequence.

Can you not afford to pay for the cap to be removed? I do that, it's like $15/month extra or something.

I heard some people would do 'domain fronting' to mask packages as going to a web that was unmetered (e.g. Google or the providers own site). But I never tried it, only heard of the trick when it was too old (counter back measures finally catch up). But you can try.. there it's, that rabbit hole... GL&HF!

Ive notice they not meter the Xfinity Free wifi SSID that their rented modem provides. The one where you login with your xfinity account "on-the-go". Its intended for when you are away from home. But I know someone who used it to bypass the metering.

leeching off a public wifi will be less reliable, probably significantly slower, and possibly subject to (unknown to you) use limits of their own.

pretty sure your provider has an unlimited option for a little more per-month. just upgrade to that for awhile, then go back to the capped plan when you're no longer going over its limit.

if you need to stay within a provider's monthly limit, just set 'speed limits' on your downloads so you won't go over for a month, and also so you have some bandwidth, and quota, leftover for other online 'activities'.

you could throttle your own connection to 1,157,407 bits per second (about 1 Mbps) and you'd run out every 30 days, assuming the 3 TB cap.