@teethbared For questions like this the Questions and Help subforum is the perfect place. To answer your question however, the items that have '(2024 Murkwood Seasonal)' in their description are soft-retiring at the end of this event. We don't know the exact details yet on how they will be obtainable in the future. The devs mentioned something about an idea of some sort of 'lootbox' type chest that can randomly award something soft-retired. But no exact details have been shared yet
For reference, the companions under 'Event companions' (namely the vulkiras and sludgeamanders), as well as the epic apparel set (the bloodmoon moss flytrap, foreclaws, hindclaws and mask) are the ones retiring.
The Murkwood consumed companions will return each murkwood event (so yearly) The general consumed companions return each pack event (so quarterly)
The not-epic apparel set (bogskull, mudpuppy, other colour variants of the moss set*) will return each year during the murkwood event
And the specialty items will return each year during the murkwood event.
*Note, it is easily missed but the update mentioned more colour variants of the apparel set will be released throughout the duration of the event.