First we see who took the most dismissals in the year (15 or more):

Led by newcomer K Verreynne of SA with 39, followed by Foakes (38) and Carey (37). Foakes and Carey have the most catches as keepers (37). RR Pant has the most stumpings (6). The most catches by fielders are 22 by Crawley and 21 by Root.
Now for the most dismissals in an innings (4 or more):

Carey leads with 6 dismissals, followed by Verreynne and Billings (5). Many others have 4 dismissals. Blundell appears to have the most stumpings (2). 3 players have 4 catches as fielders.
Most dismissals in a match (6 or more):

Led by Carey with 9, followed by several with 7. The most stumpings are 3 by Nurul Hasan and Blundell. The most catches by a fielder are 6 by Latham and Crawley
Highest dismissal rates (Minimum 20 innings, 0.600):

Again headed by Carey, followed by OJ Pope with a combination of dismissals as a keeper and fielder. The best rate by a pure fielder was 0.857 by SPD Smith followed by Crawley and Root.