/summon villager ~ ~2 ~ {VillagerData:{profession:librarian,level:5,type:plains},Offers:{Recipes:[
{buy:{id:iron_bars,Count:7},buyB:{id:feather,Count:3},sell:{id:leather_helmet,Count:1,tag:{display:{color:7047881,Name:"{\"text\":\"Speedster Helmet\",\"color\":\"blue\"}"},AttributeModifiers:
[{AttributeName:"generic.movementSpeed",Name:"generic.movementSpeed",Amount:0.033,Operation:0,UUIDLeast:111111,UUIDMost:111111,Slot:"head"},
{AttributeName:"generic.armor",Name:"generic.armor",Amount:1,Operation:0,UUIDLeast:111111,UUIDMost:111111,Slot:"head"}]
},maxUses:9999999}},
{buy:{id:iron_bars,Count:10},buyB:{id:feather,Count:6},sell:{id:leather_chestplate,Count:1,tag:{display:{color:7047881,Name:"{\"text\":\"Speedster Suit\",\"color\":\"blue\"}"},AttributeModifiers:
[{AttributeName:"generic.movementSpeed",Name:"generic.movementSpeed",Amount:0.077,Operation:0,UUIDLeast:111112,UUIDMost:111112,Slot:"chest"},
{AttributeName:"generic.armor",Name:"generic.armor",Amount:2,Operation:0,UUIDLeast:111112,UUIDMost:111112,Slot:"chest"}]
},maxUses:9999999}},
{buy:{id:iron_bars,Count:9},buyB:{id:feather,Count:5},sell:{id:leather_leggings,Count:1,tag:{display:{color:7047881,Name:"{\"text\":\"Speedster Pants\",\"color\":\"blue\"}"},AttributeModifiers:
[{AttributeName:"generic.movementSpeed",Name:"generic.movementSpeed",Amount:0.055,Operation:0,UUIDLeast:111113,UUIDMost:111113,Slot:"legs"},
{AttributeName:"generic.armor",Name:"generic.armor",Amount:1,Operation:0,UUIDLeast:111113,UUIDMost:111113,Slot:"legs"}]
},maxUses:9999999}},
{buy:{id:iron_bars,Count:6},buyB:{id:feather,Count:2},sell:{id:leather_boots,Count:1,tag:{display:{color:7047881,Name:"{\"text\":\"Speedster Boots\",\"color\":\"blue\"}"},AttributeModifiers:
[{AttributeName:"generic.movementSpeed",Name:"generic.movementSpeed",Amount:0.033,Operation:0,UUIDLeast:111114,UUIDMost:111114,Slot:"feet"},
{AttributeName:"generic.armor",Name:"generic.armor",Amount:1,Operation:0,UUIDLeast:111114,UUIDMost:111114,Slot:"feet"}]
},maxUses:9999999}}]}}