These papers aren't listed in any particular order, and any grouping is largely as I understand the problem at this time. There are other papers I'm sure I'm missing, and I haven't made through all of these yet (and a few I need to reread, a few more times!). Also, the notes are are probably somewhat subjective, but, meh, welcome to the internet.
Epidemic Algorithms for Replicated Database Maintenance - one of the first seminal papers describing gossip/epidemic protocols (1989). great read
The Peer Sampling Service: Experimental Evaluation of Unstructured Gossip-Based Implementations - First major paper to spell out the peer service in relation to gossip systems
HyParView - Hybrid Partial View, example of a peer sampling service (cares about membership & view maintenance only). maintains two partial views: active and passive; when peer from active is unreachable, a peer from passive view is promoted. special join logic when new peer tries to join.
Epidemic Broadcast Trees - Plumtree paper. Gossip overlay that uses a spanning tree. implemented in riak 2.0.
Gossip-Based Broadcast - Nice overview of gossip systems written by HyParView/Plumtree authors
SWIM: Scalable Weakly-consistent Infection-style Process Group Membership Protocol
Efficient Reconciliation and Flow Control for Anti-Entropy Protocols - adding anti-entropy to gossip exchanges. basis of cassandra's gossip subsystem
GEMS: Gossip-Enabled Monitoring Service for Heterogeneous Distributed Systems - attempts to introduce a consensus algorithm over gossip for determining some global notion of a peer's liveness; used as part of a monitoring service. each node emits a continuous heartbeat for failure detection on peers, but peers judge a target node by how rounds of gossip it has been since it saw an update from that target, which is a (semi-)subjective measurement.
Spatial Gossip and Resource Location Protocols
Failure Detectors (not specifically gossip, pre se, but close enough for my needs)A Gossip-Style Failure Detection Service - not dissimilar to cassandra's basic notion of failure detection. based on random gossip and a heartbeat counter
The ϕ Accrual Failure Detector - output a suspicion level of a node based on received heartbeat rate. a modified version is used in cassandra.
The Failure Detector Abstraction