Your search for "qsfp28" revealed the following:
nVidia Mellanox MSN3700-CS2R 32x 100GB QSFP28 F-B Airflow (C2P) Onyx Switch
SKU: NSB-6726
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
NEW Dell S5232F-ON EMC S 32x 100GB QSFP28 2x 10GB SFP+ F-B Air No OS10 Switch
SKU: NSN-9942
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Nvidia Mellanox MSN2410-BB2F 48x 10GB SFP28 8x QSFP28 B-F Air (P2C) Onyx Switch
SKU: NSB-6754
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
nVidia Mellanox MCP1600-E001E30 1m (3ft) 100GB QSFP28 Passive DAC Cable
SKU: NSB-4592
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
NEW HPE JH390A FlexFabric 5940 Series 48x 10GB SFP+ 6x 100GB QSFP28 Switch
SKU: NSN-9323
Condition: New
Shipping: Overnight Options
Warranty: 365 days
NEW Dell N3224F-ON-RA 24x 1GB SFP 4x 10GB SFP+ 2x 100GB QSFP28 B-F OS6 Switch
SKU: NSN-9975
Condition: New
Shipping: Overnight Options
Warranty: 365 days
NEW Cisco N9K-C93240YC-FX2 48x 25GB SFP 12x 100GB QSFP28 B-F Airflow Switch
SKU: NSN-1801
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Nvidia Mellanox MMA1L10-CR 100GB BASE-LR4 1310nm SMF LC QSFP28 Transceiver
SKU: NSB-3079
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
Cisco N9K-C93180YC-EX-WS 48x 25GB SFP+ 6x 100GB QSFP28 F-B Switch SmartNet Clear
SKU: NSB-3823
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
NEW Juniper QFX5210-64C-AFO 64x 100GB QSFP28 F-B Airflow Switch
SKU: NSN-3636
Condition: New
Shipping: Overnight Options
Warranty: 365 days