Crawlori is a powerful crawler developed by Functori. It allows to crawl Tezos blockchain in a very fast and modular way.
A strong and rich filter system allows you to crawl only the data that you want like monitoring an account or a smart contract, etc.
Moreover, a callback mechanism allows some customization of the data collected by the crawler. When an operation hits your filters, you can decide whatever you want to do with it (display it, add it to another database, etc.).