Can You mention some useful commands that can help discover interesting details about remote IPs/servers?

Here is what i have found useful:

Discover IP of a domain

host domain
dig +short domain

Discover hosting provider behind IP or domain

whois IPorDomain

Shows open ports and services running on it (-sV). Port scan can cause ur IP be banned.

nmap -sV IPorDomainHere

Discover some subdomains

dnsmap domain

Discover web server IP that is hiding behind Cloudflare

python3 --target domain
dig txt domain