Planning Poker is a collaborative game that team members play to reach consensus in the estimations. Each team member has a set of poker cards with values like 0, 1, 2, 3, 5, 8, 13, 20, 40 and 100, which represent the Story points. The Product Owner describes the story that needs to be estimated, and then each member selects a card that represents their estimate. If there is a large discrepancy, the team discusses the story further, and estimate is done again until consensus is reached. This process considers different perspectives and estimates are more accurate.

Affinity Estimating is another collaborative technique. In this process, the Agile team takes individual user stories and sorts them by size or complexity. These stories are often written on cards, and the team sorts them into columns. This sorting can be done on a table or wall. This provides a visualization of the relative sizes of work. The discussion that occurs during the process helps the entire team understand the work in depth. The team then assigns estimates to each column as a group.

In the T-Shirt Sizes method, different job sizes are represented by different T-shirt sizes - XS, S, M, L, XL, etc. This method is often used to give a rough estimation before the actual numbers are put down. This method is useful because it prevents the team from getting lost in details and complexity. Teams may later assign numbers to each size like 1, 2, 3, 5, and so on, similar to the way story points are used.

Ideal Days is an estimating approach in which team members estimate the amount of time they expect a user story will take to complete, assuming nothing else (meetings, other projects, etc.) is taking up time in an ‘ideal’ day. The approach is called 'ideal' because it involves the assumption that the team member can work without any interruptions. Adopting ideal days as a measure has been proved to be effective as it emphasizes the effort required to complete the task rather than the elapsed duration. This is an effective way for the team to agree upon and understand the scope of work.

Incorporated into Agile from the world of manufacturing, the Wideband Delphi technique calls upon the use of multiple rounds of assessment to arrive at an estimate. Originally created by the RAND Corporation, it is designed to encourage conversation and collaboration when it comes to estimating. The team anonymously estimates a similar item or task, then discusses the reasoning behind these estimates after which they re-estimate until a consensus is reached. The multiple iterations of estimating are intended to bring to the surface any misconceptions about scope or difficulty, and clear up ambiguities.

Using Analogous Estimating in Agile comes from the application of the Pareto Principle, also known as the 80/20 rule. This is the idea that 80% of the results come from 20% of the work. The Analogous Estimating technique is built around the concept of comparing the task at hand to similar tasks in the past. While it is less accurate than other techniques, it is often far quicker, and quite sufficient for getting an overall rough estimate.

The Bucket System is a fast and collaborative Agile Estimation Technique. Work items are placed in 'buckets' or groups, instead of being individually scored. Teams can collaboratively discuss each item to decide on its right 'bucket'. This promotes discussion among stakeholders, and different perspectives can be used to assess the difficulty and time involved in a piece of work. It is a quick and relative estimation method that helps in prioritizing work items.

Dot Voting, also referred to as 'Multi-voting', is often used as a decision-making technique in Agile software development. However, it can also be used as an estimation technique, particularly for gauging the level of effort for large backlogs. Every team member votes on each work item by assigning dots to it (the more dots, the greater the effort). The total number of dots provides an estimate of the effort involved in the task. This democratic system encourages further discussion and the dot count provides insight as to the team’s perspective on the depth of work involved.

The Fibonacci sequence is an agile estimation technique that uses the Fibonacci sequence (numbers generated by adding the two previous numbers together: 0, 1, 2, 3, 5, 8, 13, and so on) to provide a more accurate estimate of the complexity and time involved in delivering a user story. Unlike linear measurement scales, the Fibonacci sequence acknowledges the uncertainty inherent in estimating larger and more complex stories. The further out the sequence goes, the less precise the estimate becomes, which is actually a realistic reflection of what happens when teams deal with complex work.

Large, Uncertain, Small (LUS) is an agile estimation technique used as a way to categorize work based on complexity and uncertainty. 'Large' encompasses pieces of work that have known high complexity and a high degree of uncertainty, 'Uncertain' encompasses those with a moderate level of both, while 'Small' includes those with a low degree of uncertainty and complexity. This technique allows for a quick, relative sizing that aids in understanding the level of effort any given piece of work is likely to require.

The Ordering Method is best used for backlog prioritization but can be effectively utilized for estimation too. The team puts items to be estimated up for discussion. These items are then ordered from the most simple to the most complex. The team doesn’t assign any quantitative value to the items. Instead, the result visualizes the relative complexity of the items to each other. It’s not about the precision of the estimation but about understanding the amount of work that needs to be done.

Story points is a unit of measure for the amount of work it will take to complete a particular task. Rather than estimating this effort in hours or days, teams assign a point value to the task based on complexity, size or risk involved with it. This technique is abstract and requires the team to compare the size of new user stories to previously completed stories for reference. This allows teams to be less precise with their estimations, enabling them to focus more on delivering value incrementally, which aligns with the principles of Agile methodology.

Velocity tracking is an Agile estimation technique whereby teams track how much work product they can produce in a given time frame, often one sprint. This measure of completed work is typically reported in story points. By averaging the velocity over a few iterations, the team can forecast with more accuracy how much work they can do in the future sprints. This then influences planning and scheduling decisions, and helps balance team commitments and stakeholders' expectations. This technique aligns with inspect-and-adapt principle in Agile, as it facilitates continuous learning and improvement.

Proportional estimating is an Agile estimation technique which compares features or functionalities of a project in terms of size or complexity, to provide the relative estimate. Often this technique can be faster than other methods as it requires less granularity. However, it also assumes that the complexity and effort required for a certain type of task will be relatively consistent across the project. This technique is most appropriate when there are similar tasks or features to compare.

Use case points is an Agile estimation technique that considers the various aspects of a use case to estimate the effort required. It looks at the number of actors, complexity of the use case, and the technical environment to assign a point value. This method aims to quantify the functional size of a software project and the effort needed to develop it. It’s especially effective when use cases have already been detailed, and the project is somewhat traditional in nature.

Cumulative Flow Diagrams (CFDs) help Agile teams visualize and manage their work in progress. In a CFD, the horizontal axis represents time, and the vertical axis is the amount of work. Stacked areas represent the amount of work in different states. This diagram can provide an estimate in understanding how work is flowing through the process, and could predict lead times and identify bottlenecks, facilitating an early response to issues that may threat project delivery timelines. As such, it reflects Agile's focus on fostering transparency and early problem detection.