diff --git a/Sources/JSONAPIArbitrary/Attribute+Arbitrary.swift b/Sources/JSONAPIArbitrary/Attribute+Arbitrary.swift
new file mode 100644
index 0000000..5c3ddb5
--- /dev/null
+++ b/Sources/JSONAPIArbitrary/Attribute+Arbitrary.swift
@@ -0,0 +1,20 @@
+//
+//  Attribute+Arbitrary.swift
+//  JSONAPIArbitrary
+//
+//  Created by Mathew Polzin on 1/15/19.
+//
+
+import SwiftCheck
+import JSONAPI
+
+extension Attribute: Arbitrary where RawValue: Arbitrary {
+	public static var arbitrary: Gen<Attribute<RawValue>> {
+		return RawValue.arbitrary.map { .init(value: $0) }
+	}
+}
+
+// Cannot extend TransformedAttribute here
+// because there is no way to guarantee that an arbitrary
+// RawValue will successfully transform or that an
+// arbitrary Value will successfully reverse-transform.
diff --git a/Sources/JSONAPIArbitrary/Entity+Arbitrary.swift b/Sources/JSONAPIArbitrary/Entity+Arbitrary.swift
new file mode 100644
index 0000000..b686057
--- /dev/null
+++ b/Sources/JSONAPIArbitrary/Entity+Arbitrary.swift
@@ -0,0 +1,45 @@
+//
+//  Entity+Arbitrary.swift
+//  JSONAPIArbitrary
+//
+//  Created by Mathew Polzin on 1/14/19.
+//
+
+import SwiftCheck
+import JSONAPI
+
+extension NoMetadata: Arbitrary {
+	public static var arbitrary: Gen<NoMetadata> {
+		return Gen.pure(.none)
+	}
+}
+
+extension NoLinks: Arbitrary {
+	public static var arbitrary: Gen<NoLinks> {
+		return Gen.pure(.none)
+	}
+}
+
+extension NoAttributes: Arbitrary {
+	public static var arbitrary: Gen<NoAttributes> {
+		return Gen.pure(.none)
+	}
+}
+
+extension NoRelationships: Arbitrary {
+	public static var arbitrary: Gen<NoRelationships> {
+		return Gen.pure(.none)
+	}
+}
+
+extension Entity: Arbitrary where MetaType: Arbitrary, LinksType: Arbitrary, Description.Attributes: Arbitrary, Description.Relationships: Arbitrary, EntityRawIdType: Arbitrary {
+	public static var arbitrary: Gen<Entity<Description, MetaType, LinksType, EntityRawIdType>> {
+		return Gen.compose { c in
+			Entity(id: c.generate(),
+				   attributes: c.generate(),
+				   relationships: c.generate(),
+				   meta: c.generate(),
+				   links: c.generate())
+		}
+	}
+}
diff --git a/Sources/JSONAPIArbitrary/Id+Arbitrary.swift b/Sources/JSONAPIArbitrary/Id+Arbitrary.swift
index 17b7e23..fbf6c32 100644
--- a/Sources/JSONAPIArbitrary/Id+Arbitrary.swift
+++ b/Sources/JSONAPIArbitrary/Id+Arbitrary.swift
@@ -8,6 +8,12 @@
 import SwiftCheck
 import JSONAPI
 
+extension Unidentified: Arbitrary {
+	public static var arbitrary: Gen<Unidentified> {
+		return Gen.pure(.init())
+	}
+}
+
 extension Id: Arbitrary where RawType: Arbitrary {
 	public static var arbitrary: Gen<Id<RawType, IdentifiableType>> {
 		return RawType.arbitrary.map { Id(rawValue: $0) }
diff --git a/Sources/JSONAPIArbitrary/Relationship+Arbitrary.swift b/Sources/JSONAPIArbitrary/Relationship+Arbitrary.swift
new file mode 100644
index 0000000..df1dd75
--- /dev/null
+++ b/Sources/JSONAPIArbitrary/Relationship+Arbitrary.swift
@@ -0,0 +1,52 @@
+//
+//  Relationship+Arbitrary.swift
+//  JSONAPIArbitrary
+//
+//  Created by Mathew Polzin on 1/15/19.
+//
+
+import SwiftCheck
+import JSONAPI
+
+extension ToOneRelationship: Arbitrary where Identifiable.Identifier: Arbitrary, MetaType: Arbitrary, LinksType: Arbitrary {
+	public static var arbitrary: Gen<ToOneRelationship<Identifiable, MetaType, LinksType>> {
+		return Gen.compose { c in
+			return .init(id: c.generate(),
+						 meta: c.generate(),
+						 links: c.generate())
+		}
+	}
+}
+
+extension ToOneRelationship where MetaType: Arbitrary, LinksType: Arbitrary {
+	public static func arbitrary<E: EntityType>(givenEntities: [E]) -> Gen<ToOneRelationship<Identifiable, MetaType, LinksType>> where E.Id == Identifiable.Identifier {
+
+		return Gen.compose { c in
+			let idGen = Gen.fromElements(of: givenEntities).map { $0.id }
+			return .init(id: c.generate(using: idGen),
+						 meta: c.generate(),
+						 links: c.generate())
+		}
+	}
+}
+
+extension ToManyRelationship: Arbitrary where Relatable.Identifier: Arbitrary, MetaType: Arbitrary, LinksType: Arbitrary {
+	public static var arbitrary: Gen<ToManyRelationship<Relatable, MetaType, LinksType>> {
+		return Gen.compose { c in
+			return .init(ids: c.generate(),
+						 meta: c.generate(),
+						 links: c.generate())
+		}
+	}
+}
+
+extension ToManyRelationship where MetaType: Arbitrary, LinksType: Arbitrary {
+	public static func arbitrary<E: EntityType>(givenEntities: [E]) -> Gen<ToManyRelationship<Relatable, MetaType, LinksType>> where E.Id == Relatable.Identifier {
+		return Gen.compose { c in
+			let idsGen = Gen.fromElements(of: givenEntities).map { $0.id }.proliferate
+			return .init(ids: c.generate(using: idsGen),
+						 meta: c.generate(),
+						 links: c.generate())
+		}
+	}
+}