For the past several years I've been using WC alts, first in F2P and then in P2P when it made sense. Magic Logs were pretty decent AFK cash. Basically all of my alts need to pay for their own bonds.
Recently switched over to fishing since it's over twice as good. Infernal eels require 80 fishing, a fire cape, and ice gloves. They are supposedly 250k-300k gp/hr. While there was some work to be done to set it up, it's definitely paying off now!
I did Trout/Salmon in F2P and Barbarian Fishing on several of my accounts until 62-63 fishing. From there I did Monkfish on my Med and Tuna/Swordfish in the Fishing Guild on my Pure and Zerk. From 76 - 80 it was Sharks all around.
Here's the fishing loot from 62/63 - 80 fishing on all 3 of those accounts:
MED - Sabre Wraith (105 cb)
ZERK - Booty Sabre (85 cb)
PURE - Sabre Ghost (79 cb)
This is the loot from when my Main did Infernal Eels up to 260k Tokkul for an Onyx (which was roughly 80 - 86 fishing). That did not take long, it was FAST. My main is now doing Sacred Eels and collecting Zulrah's scales, while also gaining cooking xp for each Eel sliced. Infernal eels are faster and better money than Sacred, but the plan is to do 99 fishing and cooking simultaneously there on the main, and stick with Infernal Eels on the alts.
I'm expecting to take in significant income from these alts over the next few months, and probably get them all to 99 fishing eventually. Since this method is, in my opinion, the 100% most ideal option for AFKing using Chrome Remote Desktop, I'll be fishing some serious hours on all of the accounts while multitasking other things IRL. It should be very easy to pull 14m a week per account. I'll post an update in a week or two.