Pt-query-digest analyzes slow query logs and query logs to rank queries by usage statistics. It collects queries for easy analysis with tools like Pt-Visual-explain. Pt-table-checksum checks replication integrity between MySQL masters and slaves by comparing checksums of data chunks. Pt-table-sync synchronizes table data between servers by copying data in chunks and checking primary keys. Pt-Online-Schema-Change (Pt-OSC) allows modifying table structures like adding columns without locking by creating a new table, triggers for changes, and swapping the tables. Pt-kill helps kill queries matching filters like specific users, databases, commands or patterns.