Your search for "QSFP28" revealed the following:
NEW Dell S4112F-ON-RA 12x 10GB SFP+ 3x 100GB QSFP28 B-F No OS10 Switch
SKU: NSN-9959
Condition: New
Shipping: Overnight Options
Warranty: 365 days
NEW Cisco N9K-X9732C-EX 32x 100GB QSFP28 Switch Line Card
SKU: NSN-1826
Condition: New
Shipping: Overnight Options
Warranty: 365 days
NEW HPE Q9E63A M-Series SN2010M 18x 25GB SFP28 4x 100GB QSFP28 B-F Air Switch
SKU: NSN-0072
Condition: New
Shipping: Overnight Options
Warranty: 365 days
NEW Nvidia Mellanox MSN2410-BB2F 48x 10GB SFP28 8x QSFP28 B-F Air Onyx Switch
SKU: NSN-9264
Condition: New
Shipping: Overnight Options
Warranty: 365 days
NEW Cisco N3K-C36180YC-R 48x 25GB SFP+ 6x 100GB QSFP28 B-F Airflow (DC) Switch
SKU: NSN-0235
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Fiberstore Q-4S2802 2m 100GB QSFP28 to 4x 25GB SFP28 DAC Breakout Cable
SKU: NSB-9823
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
Cisco QSFP-100G-AOC20M 20m 100GB QSFP28 Active Optical Cable
SKU: NSH-8873
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
Juniper EX4650-48Y-DC-AFI 48x 25GB SFP28 8x 100GB QSFP28 B-F Airflow
SKU: NSH-8961
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
NEW Dell S4148T-ON-RA 48x 10GB Copper 2x 40GB QSFP+ 4x QSFP28 B-F No OS10 Switch
SKU: NSN-9965
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Dell S5232F-ON-RA 32x 100GB QSFP28 2x 10GB SFP+ Back-to-Front Air No OS10 Switch
SKU: NSB-9765
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days