I'm using Jim Dunlop Americana tri plectrums. They are for mandolins but they work me on bass.
https://www.google.co.uk/search?q=jim+dunlop+americana+picks&safe=active&client=ms-android-h3g-gb&sa=X&biw=360&bih=511&tbs=vw:g&tbm=shop&prmd=sinv&srpd=15701922228530733920&prds=epd:2665103104266572345,paur:ClkAsKraX4u9pTeghHwBkwB8fWlmzOZfYsIY3lXZiiOwk2xP4R5v8bUdhMxlJv8SNxDK7nFwnvOjfsbMATzfRfoZh93auSoQc91zIpkzcHTuuCe6EEFsyqVV7RIZAFPVH72qqzNoVQd-ukKBiHpv6vju9o4gYQ,cdl:1,cid:3183547036902911479&ved=0ahUKEwi1-rWnusvLAhWCZpoKHSEiAKEQgTYIwAEwAQ&ei=K5jsVvW4HYLN6QShxICICg