[INSTALLATION] How to know if a user agent is bad?

[PacaPop]

I've been analyzing the top user agents on each of my websites daily, but I'm struggling to know if they are legitimate users or just crawlers. Every day I find a new user agent there, and I don't know where to investigate if they're are good or bad.

Is there a website or database that shares user agents and where are they from?

What do you guys do after reading the user agents that reach your websites?
Are there any crawlers that I shouldn't block?

Until today I've blocked this ones:

• 80legs
• colly
• ALittle
• IonCrawl
• Gregarius
• axios
• python-requests
• Go-http-client
• masscan
• btc-lib-file
• SemrushBot
• Gulper
• Ruby
• FAST-WebCrawler
• ELinks
• Iframely