Evergreen

I'm gonna take this moment
And make it last forever

In a commercial context, evergreen product is merchandise that is not "seasonal" – it can be sent to shelves for an extended period without needing to be refreshed or updated. For Transformers, this means product that is "franchiseless", not tied to any flavor-of-the-year brand like a cartoon or movie.

After the live-action film series catapulted Transformers back into the public consciousness, deliberately evergreen products became increasingly common throughout the early 2010s, typically for licensed merchandise or for ancillary, value-oriented Hasbro toys. These products would typically borrow key art from a scattershot assortment of sources, such as various Generations toylines and the Legends mobile card game.

Eventually, Hasbro moved to align these sorts of products under a unified evergreen aesthetic, and began implementing a purpose-made set of Generation-1-inspired character designs, created by Emiliano Santalucia, for use on all-and-sundry licensed and in-house products. They debuted in late 2016, without fanfare, in IDW Publishing's contemporary comic line, before showing up on a wider variety of merchandise during 2017.

Products incorporating evergreen character designs

Fiction

I'm gonna give my heart away
And pray we'll stay together

IDW Publishing's original Generation 1 comic line began introducing evergreen character designs in the aftermath of the 2016 Revolution crossover event. The implementation was last-minute enough that at least one cover had to be redrawn by the artist to incorporate Optimus's evergreen design. Designs have been introduced as follows:

Starscream, beginning with The Transformers: Till All Are One #5
Optimus Prime, beginning with Optimus Prime #1
Windblade, beginning with First Strike #1
Soundwave, beginning with First Strike #2
Shockwave, beginning with Optimus Prime #19
Bumblebee, beginning with Transformers: Unicron #0

Space Ape's Transformers: Earth Wars mobile game introduced a design of their own that would be used in 2017:

Barricade, beginning with "Event Horizon".

Most main characters in Cyberverse use interpretations of evergreen designs, as do the established characters in EarthSpark.

The Rescue Bots Academy cartoon redesigned previous Aligned continuity characters, including Optimus, Bumblebee, Grimlock, and Ratchet to use their evergreen designs. Early concept art suggests this mandate was not in place at the beginning of the show's development.

Grimlock and Optimus Prime in King Grimlock both use direct translations of the evergreen designs.