For individual tournaments:

1. Olympics - once every 4 years,
2. Dubai Super Series Masters Final - once every year in the end of the year, where only 8 of the strongest players that year competing. This is the most competitive badminton competition to qualify to and win.
3. World Championship and All England - these two are on similar prestige and difficulty level.

Below these four, the ordering in terms of difficulty / prestige:

1. Premier Super Series tournaments: China, Denmark, Indonesia, Malaysia Open
2. Super Series tournaments
3. Grand Prix Gold tournaments
4. Grand Prix tournaments
5. International Series

There are non-BWF tournaments like PBL in India, CBSL in China, but these still tend to be more local in prestige.

For team events, Olympics and Thomas / Uber Cup are also quite high-prestige.