What tools does an SEO use?

There are a number of tools that are useful to an SEO

 

SEO Tool Name Platform (SE) Entry Cost Notes
Google Search Console (GSC) Google Free GSC is the number 1 tool for managing your relationship with Google. GSC can integrate with Google Analytics, Data Studio and other data integration tools as well as SEOMoz and SEMrush. GSC also has an API but features a very basic UI (compared to Google Analytics). However, its is the golden repository of keyword and page performance within the Google Search eco-sphere. 
Bing Webmaster Tools Bing Free Bing is the equivalent of GSC with some differences. Bing has a site explorer tool that maps out your site and sub-domains in an explorer-style format, which is very handy – especially if you want to envisage how a search engine sees your site/domain architecture at a sub-domain and file/folder point of view. Bing also has a site health checker tool
SEMRush Google, YouTube  From $150 pm SEMRush is a SERP tool primarily focused on Google (and recently Youtube) with support for local SEO websites (e.g. Yelp). SEMrush also has a backlink checker, keyword planning tool and site healthchecker. It also features a basic social media posting tool and a beta “share of voice feature”. SEMRush is very popular but features are becoming more and more expensive.
Moz Google, Yahoo & Bing $99 Similar to SEMrush, Moz was founded by Rand Fishkin but is a little more clunky with a lot less detail (IMHO)
AHrefs Google $99 Ahrefs is well known for its backlink hunting tools but now offers SERP, Healthcheck and keywords explorer
Google Analytics All Free  Google Analytics is the grandfather of Web Analytics tools and well integrated. The most popular is Google Universal, with GA4 being the next albeit incomplete version. GA integrates well with GSC and Google Ads and can import some information from Bing Ads (mainly as Source/Medium or UTM). 
Google Data Studio All Free GDS is a data reporting & integration tool that integrates with multiple data sources like GSC, SEMrush, Ads, Bing, etc. GDS is similar to tools like Databox, Domo etc.