When using GraphAll you may still want to filter the results, in which case you can use an Alert variable with the Filter, Sort, and Limit functions.
template graph.template {
subject = ...
body = `{{template "header" .}}
<strong>Graph Filtered Variable</strong>
<div>{{.Graph .Alert.Vars.graph_below_5 .Alert.Vars.graph_unit}}</div>
<strong>Graph Filter+Sort+Limit Variable (Maximum of 10 series)</strong>
<div>{{.Graph .Alert.Vars.graph_lowest_10 .Alert.Vars.graph_unit2}}</div>
`
}
alert os.low.memory {
template = graph.template
...
$graph_all = q("avg:300s-avg:os.mem.percent_free{host=ny-*}", "1d", "")
$graph_unit = All Systems with Less than 5 Percent Free Memory
$graph_below_5 = filter($graph_all, min($graph_all) < 5)
$graph_unit2 = Ten Systems with lowest Percent Free Memory
$graph_lowest_10 = filter($graph_all, limit(sort(min($graph_min_5),"asc"),10))
...
}