lein-ancient checks your projects or whole Leiningen environment for outdated dependencies and automatically upgrades them to current versions.
lein-thriftc compiles your Thrift IDL files and puts them on the classpath.
Lifecycle & Components
minion let's you create entry points for your applications, including command-line parsing, embedding an nREPL server, etc...
peripheral offers macros for simple component and system generation using Stuart Sierra's component library. It additionally handles things like ad-hoc subsystems, graceful rollback after initialization failures and some others.
pandect is a fast and simple hash, checksum and HMAC library.
Ring & Ronda
ronda/routing aims at decoupling routing and handlers, allowing for e.g. conditional middlewares, injection of route-based request metadata and much more.
ronda/schema translates prismatic's schema validation to HTTP requests and responses.