Received data records, each including one or more values in one or more fields, are processed to identify one or more data clusters. The processing includes: identifying tokens that each include at least one value or fragment of a value in a field or a combination of fields; generating a network representing the identified tokens, with nodes of the network representing tokens and edges of the network each representing a variant relationship between tokens; and generating a graphical representation of the network with different subsets of nodes distinguished based at least in part on values associated with nodes, where a value associated with a particular node quantifies a count of a number of instances of the token represented by that particular node appearing within the received data records.