I believe you can also buy a pass for the Al Maha and Oryx lounges. We use our Priority Pass membership to access these.
I strongly recommend Al Mourjan lounge in Doha. It is the best lounge you can buy your way into in Qatar. It is very large and roomy with better food and beverage selection (like two different Champagnes at the bar). There are two “restaurants” in that lounge, showers, work stations etc. This the lounge you get access to when flying business on Qatar.
There is also the Al Safwa lounge in Doha (for Qatar’s 1st class pax only) but you can’t buy your way into it unfortunately. This is a shame as it is just something else. They pour vintage Krug like it’s water over there and facilities include hotel style rooms with bathrooms and bedrooms, a spa, duty free shop (inside the lounge), a cigar room as well as displays of ancient artefacts from Qatar’s museum of Islamic art.