Speaking of overagers like Leason, Fagemo and Struthers, there are several somewhat interesting players that have entered UDFA eligibility:
Nikita Mikhailov, 1998-05-08 (20 years old, 2016 draft eligible), left shot C, 6'0 163 lbs, Sibir Novosibirsk KHL, 0.34 NHLe 0.2 GNHLe
Mikhailov leads his team with 15 points (9 goals) in 33 games (same NHLe as Leason's 60 in 28 in the WHL), so he isn't being carried by his teammates. Scored 48P in 63GP in the NHL last year, so is somewhat lacking scoring pedigree unfortunately.
Denis Alexeyev, 1997-10-01 (21 years old, 2016 draft eligible), right shot C, 6'0 183 lbs, Lokomotiv Yaroslavl KHL, 0.39 NHLe 0.11 GNHLe
Alexeyev is third in Lokomotiv scoring this season with 18 points (5 goals) in 33 games. Has decent scoring pedigree as he scored 18P in 23GP in the VHL alredy in the 16-17 season and played 16 games in the KHL that year (10 RS + 6 PO). Scored decently in the MHL and VHL last year though he mostly played in the KHL.
Radovan Pavlik, 1998-02-12 (20 years old, 2016 draft eligible), left shot RW, 5'9 172 lbs, Mountfield HK Czech Extraliga, 0.33 NHLe 0.13 GNHLe
Pavlik is fourth in Mountfield scoring this season with 14 points (5 goals) in 23 games. Has a good pedigree having played for the national team at all levels (U16, U17, U18, U19, U20 and senior team in the EHT). Played 18 games in the Extraliga in his draft year (no points) and scored 9 points in 9 games in the Czech U20 league last year. Had 6 points (3 goals) in 7 games in the 2018 WJC.
Charles-Édouard D'Astous, 1998-04-21 (20 years old, 2016 draft eligible), left shot D, 6'2 201 lbs, Rimouski Océanic QMJHL, 0.20 NHLe 0.04 GNHLe
D'Astous is third in Rimouski scoring this season with 37 points (8 goals) in 25 games, though how much of that is simply giving the puck to Lafrenière is hard to say. Was named captain this season and had 64 points in 66 games last year.