Watkins scored the dramatic semi-final winner against the Netherlands from off the bench, while Toney set up Harry Kane's goal against Slovakia and then scored a 'no-look' penalty in the shootout win over Switzerland. Young midfielder Mainoo was impressive after coming into the starting line-up from the start of the knockout phase.
Those contributions are likely to enhance their net worth, according to a financial expert. Speaking exclusively to Saxo, Professor Rob Wilson, of Sheffield Hallam University, revealed: "When we talk about the knock-on benefits in terms of branding for other players in the England squad, what we are really looking for are iconic moments.
"The performances of the likes of Kobbie Mainoo are also likely to make him really stand out. Ollie Watkins will be revered for the next few months and that will have an impact on his contract negotiations at Aston Villa, or could even put him in the shop window for a potential transfer to one of the so-called 'elite clubs'.
"Ivan Toney will certainly be looking for a potential move and I think Mainoo is probably the real standout for me, having come into the team at just 19 years of age. The fact he is a mainstay for Manchester United is positive as they are a globally recognised brand."
"But it's time for change and for a new chapter. Sunday's final in Berlin against Spain was my final game as England manager."
FA chief executive Mark Bullingham paid tribute to Southgate's achievements in leading England to successive European Championship finals, as well as to the semi-finals of the 2018 World Cup in his first tournament.
Bullingham indicated the process to find Southgate's successor "is now under way" and said The FA had an "interim solution in place if needed", with the team's next matches coming in the Nations League in September.