While not as common anymore, individual OKRs used to be a part of many OKR implementations. They however add a lot of complexity and are more aligned with performance management and HR processes than the other parts of OKRs why it is common to recommend to hold of on implementation or at least separate the processes between Individual OKRs and OKRs for the organisation.
The two core issues with individual OKRs are the risk of miss-alignment with team OKRs and the inclination of sand-bagging when setting goals closely related to individual performance.
When set however, most common influences for these OKRs are:
Individual OKRs many times live a life a little on the side of other OKRs and most organisations choose not to publish them transparently for the wider organisation.
This OKR is based on personal development and tries to address quantity and quality by both setting key results for the size of events (number of people listening) as well as the total number of events (needs to be at least two different).