Let’s assume we want to create a more serious list than this. Which athletes would make it? Given that track & field (athletics) is the most foundational sport of them all, I though it would make a good starting point.
There are so many events in track & field for both sexes that it takes something truly special to deserve a mention. Being merely generationally good at a single event does not cut it. You need to be arguably the greatest ever at what you do. This disqualifies Allyson Felix who did make ESPN’s list: she’s best known for her consistency, not individual dominance. Yet track and field athletes that do qualify are numerous:
Usain Bolt, 100–200 meters
▪ 6 individual Olympic Golds (3 x 100m, 3 x 200m)
▪ 7 individual WC Golds (3 x 100m, 4 x 200m)
▪ 1-time Diamond League winner (1 x 100m)
▪ 7 individual world records (3 x 100m, 2 x 200m, 1 x 150m, 1 x i100m)
Kenenisa Bekele, 5000/10000 meters
▪ 3 individual Olympic Golds (1 x 5000m, 2 x 10000m)
▪ 5 individual WC Golds (1 x 5000m, 4 x 10000m)
▪ 1 individual indoor WC Gold (1 x 3000m)
▪ 11 individual cross-country WC Golds (5 x short, 6 times long)
▪ 6 individual WRs (1 x 5000m, 2 x 10000m, 1 x i2000m, 1 x indoor 2 miles, 1 x i5000m)
▪ Came within 2 seconds of breaking the marathon world record in 2019
▪ 2 M40 master world records in the marathon (the only 40-year-old under 2:05)
Mo Farah, 5000/10000 meters
▪ 4 individual Olympic Golds (2 x 5000m, 2 x 10000m)
▪ 6 individual WC Golds (3 x 5000m, 3 x 10000m)
▪ 1-time Diamond League winner (1 x 5000 m)
▪ 2 individual world records (1 x 1 hour run, 1 x indoor 2 miles)
Tirunesh Dibaba, 5000/10000 meters
▪ 3 individual Olympic Golds (1 x 5000m, 2 x 10000m)
▪ 5 individual WC Golds (2 x 5000m, 3 x 10000m)
▪ 4 individual cross-country WC Golds (1 x short, 2 times long, 1 x senior)
▪ 4 individual world records (1 x 5000m, 2 x i5000m , 1 x 15 km road race)
Shelly-Ann Fraser-Pryce, 60–200 meters
▪ 2 individual Olympic Golds (2 x 100m)
▪ 6 individual WC Golds (5 x 100m, 1 x 200m)
▪ 1 individual indoor WC Gold (1 x 60m)
▪ 5-time Diamond League winner (4 x 100m, 1 x 200m)
▪ 0 individual world records (fastest first 60m split ever at 6.81s)
Anita Wlodarczyk, hammer throw
▪ 3 individual Olympic Golds (1 retroactive)
▪ 4 individual WC Golds
▪ 6 individual absolute world records (all outdoors)
▪ 6 longest throws ever
Faith Kipyegon, 1500/5000 meters
▪ 2 individual Olympic Golds (2 x 1500m)
▪ 4 individual WC Golds (3 x 1500m, 1 x 5000m)
▪ 4-time Diamond League winner (4 x 1500 m)
▪ 4 individual world records (2 x 1500m, 1 x mile, 1 x 5000m)
Robert Korzeniowski, race walking
▪ 4 individual Olympic Golds (1 x 50km in 1996; 2 x 50km & 1 x 20km in the 2000s)
▪ 3 individual WC Golds (1 x 50km in 1997; 2 x 50km in the 2000s)
▪ 0 individual indoor WC Golds (1 x 5000m walk silver)
▪ 2 individual world records (2 x 50km)
Yelena Isinbayeva, pole vault
▪ 2 individual Olympic Golds
▪ 3 individual WC Golds
▪ 4 individual indoor WC Golds
▪ 17 individual absolute world records (15 outdoors, 2 indoors)
Barbora Spotakova, javelin throw
▪ 2 individual Olympic Golds
▪ 3 individual WC Golds
▪ 5-time Diamond League winner
▪ 1 individual absolute world record (outdoors)
Yulimar Rojas, triple jump
▪ 1 individual Olympic Gold
▪ 4 individual WC Golds
▪ 3 individual indoor WC Golds
▪ 3-time Diamond League winner
▪ 2 individual absolute world records (1 outdoors, 1 indoors)
Elaine Thompson-Herah, 60–200 meters
▪ 4 individual Olympic Golds (2 x 100m, 2 x 200m)
▪ 0 individual WC Golds (1 x 200m silver, 1 x 100m bronze)
▪ 0 individual Indoor WC Golds (1 x 60m bronze)
▪ 3-time Diamond League winner (3 x 100m)
▪ 0 individual world records (2nd fastest woman ever, fastest top speed ever at 39.7 km/h)
Hicham El Guerrouj, 1500/5000 meters
▪ 2 individual Olympic Golds (1 x 1500m, 1 x 5000m)
▪ 4 individual WC Golds (2 x 1500m in the 1990s, 2 x 1500m in the 2000s)
▪ 3 individual indoor WC Golds (2 x 1500m in the 1990s, 1 x 3000m in the 2000s)
▪ 5 individual world records (1 x 1500m, 1 x mile, 1 x 2000m, 2 indoor 1500m/mile)
Ashton Eaton, heptathlon/decathlon
▪ 2 individual Olympic Golds (2 x decathlon)
▪ 2 individual WC Golds (2 x decathlon)
▪ 3 individual Indoor WC Golds (3 x heptathlon)
▪ 5 individual world records (3 x heptathlon, 2 x decathlon)
David Rudisha, 800 meters
▪ 2 individual Olympic Golds (2 x 800m)
▪ 2 individual WC Golds (2 x 800m)
▪ 2-time Diamond League winner (2 x 800m)
▪ 4 individual world records (3 x 800m, 1 x 500m)
Ryan Crouser, shot put
▪ 2 individual Olympic Golds
▪ 2 individual WC Golds
▪ 1 individual indoor WC Gold
▪ 2 individual absolute world records (both outdoors)
Karsten Warholm, 400m/400m hurdles
▪ 1 individual Olympic Gold (1 x 400m hurdles)
▪ 3 individual WC Golds (3 x 400m hurdles)
▪ 0 individual indoor WC Golds (1 x 400m silver)
▪ 2-time Diamond League winner (2 x 400m hurdles)
▪ 4 individual world records (2 x 400m hurdles; 2 x 300m hurdles)
Mutaz Essa Barsham, high jump
▪ 1 individual Olympic Gold
▪ 3 individual WC Golds
▪ 1 individual indoor WC Gold
▪ zero world records, but did show the capability of breaking it
Armand Duplantis, pole vault
▪ 1 individual Olympic Gold
▪ 2 individual WC Golds
▪ 2 individual indoor WC Golds
▪ 3-time Diamond League winner
▪ 8 individual absolute world records (3 outdoors, 5 indoors)
Eliud Kipchoge, 3000m/5000m/marathon
▪ 2 individual Olympic Golds (2 x marathon)
▪ 1 individual WC Gold (5000m)
▪ 0 individual indoor WC Golds (1 x 3000m bronze)
▪ 2 individual world records (2 x marathon)
Sydney McLaughlin-Levrone, 400m hurdles
▪ 1 individual Olympic Gold (1 x 400m hurdles)
▪ 1 individual WC Gold (1 x 400m hurdles)
▪ 1-time Diamond League winner (1 x 400m hurdles)
▪ 4 individual world records (4 x 400m hurdles)
That's 21 athletes that are arguably the greatest ever at what they do. Some of them will add to their resumes within a couple of weeks. And I didn't even mention the Paralympics:
List of multiple Paralympic gold medalists - Wikipedia
Bottom line: top 100 athletes is an extremely demanding list to make!
EDIT: triple jumper
Christian Taylor also deserves to be called arguably the greatest ever. He may be 8 cm shy of Jonathan Edwards' WR, but otherwise his achievements are superior to the late-blooming 1990s great Edwards: 2 individual Olympic Golds, 4 individual WC Golds, 5-time Diamond League winner against a strong generation of triple jumpers.
Other athletes who deserve a mention:
- Ezekiel Kemboi (2 OG, 4 WCG) played 2nd fiddle to Said Saaeed Shaheen (aka Stephen Cherono) in the 3000m steeplechase, but started to dominate like no one else once injury problems cut Shaheen's prime short. Kemboi still did it against a strong generation, so he might be legit here.
- Valerie Adams/Vili (2 OG, 4 WCG, 4iWCG, 6 DLW) has all the achievements but the ridiculous shot put WRs set in the distant past make them (unfairly?) seem less impressive.
- Virgilijus Alekna's (2 OG, 2 WCG, 6 DLW) main problem in discus throw is the 4-time Olympic champion Al Oerter. It's tough to call Alekna the greatest rather than "just" generational.
- Sandra Elkasevic/Perkovic (2 OG, 2 WCG, 6 DLW) is a discus throw version of Valerie Adams, except challenged by her peers a bit better. Unlike Alekna, she's been at her best in the European championships though, as her record 7th title in an individual event this year shows.