Most beginners start with SQLi Dumper and stick to it, even though it's a highly outdated tool, especially when exploiting vulnerabilities. I think it's still used in 2021 because the idea of mass dumping fools people; they see a long list of injectable URLs and instantly think it's a good tool, but it has countless issues: a laggy GUI, a slow dumping process, an unknown developer, no bug fixes, limited exploiting power. Whereby "limited exploiting power", I mean that SQLiD only targets GET and POST parameters in the URI to trigger an SQL injection, and then it dumps the data from there. It doesn't scan for any vulnerability within the web application itself, like forms, and it misses a ton of vulnerabilities for other DBMS besides the common ones.
But most people genuinely don't care. For instance, sqlmap is way better than SQLiD for various reasons: it's faster, it's lightweight, it targets more DBMS, it's more customizable, but it's harder to master, so people prefer to use an old, outdated shit tool like SQLiD than learn sqlmap, which unlike SQLiD is developed and used by professionals. There are other tools, like Havij, SqlRip, SIB, but they're outdated and not worth mentioning.