diff --git a/common/src/tectonic/resources/List.md b/common/src/tectonic/resources/List.md
index b02e61e6a..96d2eaf6d 100644
--- a/common/src/tectonic/resources/List.md
+++ b/common/src/tectonic/resources/List.md
@@ -3,12 +3,14 @@
 A List is an ordered collection of objects of a specific type.
 
 Examples:
-* ```yml
+* A List of [Strings](./String)s
+  ```yml
   - "thing"
   - "thing 2"
   - "thing 3"
   ```
-* ```yml
+* A List of [Integers](./Integer)
+  ```yml
   - 1
   - 2
   - 3
diff --git a/common/src/tectonic/resources/Map.md b/common/src/tectonic/resources/Map.md
new file mode 100644
index 000000000..e64644404
--- /dev/null
+++ b/common/src/tectonic/resources/Map.md
@@ -0,0 +1,17 @@
+# Map
+
+A map is a data structure that "maps" one type (keys) to another (values).
+
+Examples:
+* Mapping [Strings](./String) to [Strings](./String)
+  ```yml
+  a: "thing"
+  b: "thing 2"
+  c: "thing 3"
+  ```
+* Mapping [Strings](./String) to [Integers](./Integer)
+  ```yml
+  a: 1
+  b: 2
+  c: 3
+  ```
diff --git a/common/src/tectonic/resources/ProbabilityCollection.md b/common/src/tectonic/resources/ProbabilityCollection.md
new file mode 100644
index 000000000..07ba72ca8
--- /dev/null
+++ b/common/src/tectonic/resources/ProbabilityCollection.md
@@ -0,0 +1,50 @@
+# ProbabilityCollection
+
+A Probability Collection is a representation of a weighted pool.
+
+Example:
+* `a` has a 1/5 (20%) chance, `b` and `c` both have a 2/5 (40%) chance.
+  ```yml
+  - a: 1
+  - b: 2
+  - c: 2 
+  ```
+
+# Weighted Pool
+
+A weighted pool is a way to randomly select one of many objects from a "pool" based on "weight".
+
+## Pools
+A pool is a list of objects from which selections will be pulled.
+
+## Weight
+Weight is the *relative* probability that any object will be selected from the pool. Each object in the pool has a
+weight, meaning the chance of object O being selected from pool P is `weight(O)/sum(weight(P_n))`.
+
+## Example
+Here's an example pool:
+```yaml
+OPTION_A: 2
+OPTION_B: 1
+OPTION_C: 1
+```
+In this YAML-based pool, the keys are the objects, and the values are the weights. If we want the probability that
+`OPTION_A` will be selected, we sum all weights, and divide the weight of `OPTION_A` by that sum.  
+`2 + 1 + 1 = 4`   
+Therefore the probability that OPTION_A will be selected is `2/4`, or 50%.
+
+## Manipulating weights to get a desired probability
+What if we want Option A to have a 60% chance of being selected? This requires manipulating the weights of all objects
+in the pool, since with B and C having a weight of 1, there is no integer weight that can be assigned to A that will
+give it a probability of 60%. What is usually done is that the weights are given a set sum that is easy to work with.
+Usually this is 100, since with a sum of 100, every object's weight is equal to the percent chance it will be selected.
+By applying this to the above example, we can produce this pool that has a 60% chance of A being selected:
+```yaml
+OPTION_A: 60
+OPTION_B: 20
+OPTION_C: 20
+```
+
+## Use Cases
+Sometimes, it is undesirable to have an equal probability of all objects being selected, so you may want to "weight"
+some objects higher, so they are selected more often.
diff --git a/common/src/tectonic/resources/Set.md b/common/src/tectonic/resources/Set.md
new file mode 100644
index 000000000..ef74a4f0d
--- /dev/null
+++ b/common/src/tectonic/resources/Set.md
@@ -0,0 +1,17 @@
+# Set
+
+A Set is very similar to a [List](./List), except it is *unordered*.
+
+Examples:
+* A Set of [Strings](./String).
+  ```yml
+  - "thing"
+  - "thing 2"
+  - "thing 3"
+  ```
+* A Set of [Integers](./Integer).
+  ```yml
+  - 1
+  - 2
+  - 3
+  ```