Free agents aren't exactly common around this time of year, and in terms of strikers Rossi is definitely the most notable and probably best out of the ones available (that aren't geriatric - Keane and Berbatov are available but I don't want a 38 year old up front). Nasri's the only attacking player notable enough to be a marquee apart from those three. https://www.transfermarkt.com/statistik/vertragslosespieler
Alternatively, we could look for players whose contracts end on January - this is what I think we'll be doing. Brazilian league, or any number of other North American/South American/Asian leagues (could be looking at a couple MLS or Chinese league players?). The only ones I'd see the FFA spending big on are David Villa, Fernando Torres and Ezequiel Lavezzi, but other options include Graziano Pelle and Jonatan Soriano (Basti Schweinsteiger too if we want an alright replacement for Kopa). https://sofifa.com/players?lg%5B%5D=39&lg%5B%5D=20...