This is not an exhaustive list. Most of these species got extinct during the earliest subdivision of the Pleistocene (Gelasian).

Sharks:

Lamniformes

- Carcharodon hastalis (Early Pleistocene - Calabrian)

- Parotodus benedenii (Early Pleistocene - Calabrian)

Carcharhiniformes

- Hemipristis serra (Middle Pleistocene - Chibanian)

Cetaceans:

Mysticetes

- Balaenoptera bertae (Early Pleistocene - Gelasian)

- Eschrichtius akishimaensis (Early Pleistocene - Gelasian)

- Herpetocetus sp. (Early Pleistocene)

- Plesiocetus sp. (Early Pleistocene - Gelasian)

- Balaenula sp. (Early Pleistocene)

Delphinidae

- Platalearostrum hoekmani (Early Pleistocene)

- Orcinus citoniensis (Early Pleistocene - Gelasian)

- Orcinus paleorca (Middle Pleistocene - Chibanian)

- Hemisyntrachelus sp. (Early Pleistocene - Gelasian)

- Rododelphis stamatiadisi (Early Pleistocene)

Phocoenidae

- Semirostrum ceruttii (Early Pleistocene - Calabrian)

Physeteridae

- Scaldicetus sp. (Early Pleistocene - Gelasian)

- Hoplocetus sp. (Early Pleistocene - Gelasian)

Pinnipeds:

Odobenidae

- Ontocetus posti (Early Pleistocene)

Phocidae

- Neomonachus tropicalis (Late Holocene)

- Zalophus japonicus (Late Holocene)

Sirenia:

- Hydrodamalis gigas (Late Holocene)

The Wikipedia page states that P. benedenii persisted until 1.1 million years ago (Calabrian - Early Pleistocene), yet i cannot find any evidence of a Pleistocene occurrence of the species.

This depiction is still a bit too similar to the great white shark, in some aspects. But the body plan is spot on. Slender body and long dorsal/pectoral fins with rounded tips, similar to I. paucus.

Unfortunately i don't know who is behind this art.

Source (with timecode): https://youtu.be/gZ8BgsLpRgw?si=bzK4yCdw-QXhrDNX&t=508

Gmod sighting in real life

This is the last living species of the genus Hemipristis, the others 4 species are all extinct - including the great white sized Hemipristis serra that disappeared approximately 300 000 years ago.

Despite the fact that the snaggletooth shark (Hemipristis elongata) is still around today, it was discovered decades after the extinct Hemipristis serra was described. This is why it is also known as the "fossil shark".

Hemipristis elongata is exclusively found in the coastal waters of the Indo-West Pacific. It has large serrated teeth in the upper jaw and hooked teeth in its lower jaw.

It appears to be naturally uncommon in most places where it occurs.