G.SKILL Announces New DDR4 Specifications for Intel Kaby Lake Platform - DDR4-4266MHz CL19 8GBx2 & DDR4-4133MHz CL19 8GBx4 - G.SKILL International Enterprise Co., Ltd.
G.SKILL 32GB (4 x 8GB) TridentZ RGB Series DDR4 PC4-34100 4266MHz Desktop Memory Model F4-4266C17Q-32GTZR at Amazon.com
G.SKILL DDR4-4266MHz 64GB RGB Trident Memory Kits Released – GND-Tech
Here is why LPDDR4x-4266 RAM seems considerably faster when coupled with Intel Tiger Lake-U CPUs compared to equivalent AMD Renoir APUs - NotebookCheck.net News
Hynix CJR 4266 MHz CL-18-22-22-28 (more in comments) : r/overclocking