There are 4 different proxy types: HTTP, HTTPS, Socks 4 and Socks 5. The main difference between HTTP and Socks proxies is that the former can only direct web traffic, whereas the latter can route all types of data. If you only want to use a proxy for your browser, the proxy type is irrelevant. Note that visiting a website through https is always end-to-end encrypted, no matter if it's a HTTP or HTTPS proxy.
Anonymity levels among proxies are commonly classified as Elite, Anonymous and Transparent proxies (or Level 1 to 3). While both Elite and Anonymous proxies hide your IP from the destination host, the latter does not hide the fact that it is a proxy and sends additional headers in the request. We call this Proxy Detection via Connection, whereas Proxy Detection via Database detects wheter a proxy is used by checking the IP against known proxy databases. If one or both are detected, we list the proxy as YES in the Proxy Detection (PD) column. Having NO in the PD column always means it passed both checks undetected (Proxy type Elite without being in a known proxy ip range). Transparent proxies are not anonymous, as they forward your IP address in those additional headers. Your IP is still masked, but it's easy for the destination server to detect your real IP here, therefor transparent proxies are listed as Anon NO and PD YES, as they are detected as proxy via connection.