I read quite a few books touching on sharding, but one book puts it succinctly into the big picture of noSQL, big data, web2.0 and cloud — [[cloud architecture patterns]]
PWM partition — The position database in PWM was partitioned into regions like Asia, Europe, Latam, … This is an early example of sharding.
custom built — early sharding tends to be custom-built, like PWM. Nowadays standard sharding support is available in many databases, so no more custom-built.
noSQL and SQL databases — both support sharding
Autonomous — Shards do not depend on (or reference) each other.
Static data tables — are not sharded but replicated.