Best place to farm Fools Chain.

Wastelands of death free quest in Camelot. Hidden village in Camelot also has a decent drop rate (slightly worse than wastelands) but you can get scarabs and caster gems there too.

Nerofest xD

The upcoming hunter quest with demons will have a moderate drop rate for chains as well. But yeah, wastelands of death is the best free quest for getting chains.